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# Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance

Jean-charles Vauthier

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## To cite this version:

Jean-charles Vauthier. Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance. PLoS ONE, In press, 10.1371/journal.pone.0338637. hal-05411453

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<table><tr><td>Manuscript Number:</td><td>PONE-D-25-52862R1</td></tr><tr><td>Article Type:</td><td>Research Article</td></tr><tr><td>Full Title:</td><td>Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance</td></tr><tr><td>Short Title:</td><td>Living with T1D in Ultra-Endurance</td></tr><tr><td>Corresponding Author:</td><td>Jean-Charles VAUTHIER, MD<br>UL: Universite de Lorraine<br>Vandoeuvre Lès Nancy, FRANCE</td></tr><tr><td>Keywords:</td><td>Type 1 Diabetes; Endurance training; Chronic disease; self-management; grounded theroy; Resilience</td></tr><tr><td>Abstract:</td><td>Background This study explores how people with type 1 diabetes experience ultra-endurance sports, focusing on identity, self-management, and psychosocial impacts through a qualitative approach. Methods and findings This qualitative study used a constructivist grounded theory approach. Thirteen semi-structured interviews were conducted with French-speaking adults living with T1D who had completed at least one marathon or ultra-endurance race. Data were analyzed inductively through line-by-line coding, focused coding, and thematic categorization, supported by NVivo® software and reported in accordance with COREQ guidelines. Four major themes emerged: (1) a progressive process of acceptance, from the shock of diagnosis to identity integration; (2) the ambivalence of being “ill,” with tensions between medical status and personal identity; (3) the mental load of diabetes management, intensified by ultra-endurance but mitigated by adaptive strategies and peer support; and (4) sport as a transformative space for self-affirmation, resilience, and advocacy. Participants described how ultra-endurance helped them reclaim agency, reframe their illness, and inspire others. Conclusions Ultra-endurance sports offer a unique context for identity reconstruction and empowerment among people with T1D. Far from being a barrier, the illness can become a driver of personal growth and social visibility. These findings highlight the importance of recognizing experiential knowledge in chronic disease management and call for more inclusive, patient-centered approaches in healthcare and research.</td></tr><tr><td>Order of Authors:</td><td>Jean-Charles VAUTHIER, MD<br>Lucie Choley<br>Bernard Kabuth, PhD</td></tr><tr><td>Opposed Reviewers:</td><td></td></tr><tr><td>Response to Reviewers:</td><td>Dear Reviewers, I would like to sincerely thank both reviewers for the time and effort devoted to reviewing my manuscript, which explores the lived experience of chronic illness—specifically type 1 diabetes—in the context of ultra-endurance sports. Your comments and suggestions have been extremely valuable and have significantly improved the quality of this work. Revisions Implemented •Title: The title has been revised to make it more precise and aligned with PLOS ONE style guidelines. •Participant Table: The table has been enriched with additional data from interviews (age, sex, diabetes duration, technology use, type of race), while respecting ethical constraints. Race names were omitted to preserve anonymity. •Ethics and Data Access: The ethics approval statement now appears only in the Methods section. The institutional contact for data access has been corrected (Data Access Committee, Université de Lorraine). •References: The reference list was checked for retracted articles. Two suggested</td></tr></table>
references could not be retrieved despite extensive searches. However, the concept of supercrip narratives was incorporated through the publication by Williams et al. (2021).

*Sample Justification: The sample size (n = 13) is consistent with qualitative research standards and reflects the rarity of the target population (likely fewer than one hundred ultra-endurance athletes with type 1 diabetes in France). The gender distribution (15% women) mirrors the reality of ultra-endurance events, where female participation remains limited but is gradually increasing.

*Reflexivity: I expanded the description of my dual role as both a physician and a person living with type 1 diabetes, and detailed strategies to minimize bias (reflexive journaling, triangulation with co-authors). This is addressed in the Methods section and acknowledged in the limitations.

*Clinical Implications: A paragraph was added to highlight how endocrinologists and primary care physicians can support patients pursuing ultra-endurance goals through individualized guidance and collaborative care.

*Language and Style: Several sentences were revised to improve clarity and readability, following your recommendation for a more fluent style.
To facilitate your review, a detailed point-by-point response table is provided in the file "response to reviewers".

Once again, thank you for your constructive feedback. I hope this revised version meets your expectations and reflects the quality standards of PLOS ONE.
Best regards

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Dr. Jean-Charles Vauthier
Université de Lorraine
Département de médecine générale
9 avenue de la forêt de Haye
54500 Vandoeuvre-lès-Nancy, France
jean-charles.vauthier@univ-lorraine.fr
+33 6 87 70 16 21

**To the Editors of PLOS ONE,**

I am pleased to submit our manuscript entitled **"Chronic illness and extreme performance: Type 1 Diabetes put to the test by Ultra-Endurance"** for consideration for publication in *PLOS ONE*.

This qualitative study explores the lived experience of individuals with type 1 diabetes (T1D) who engage in ultra-endurance sports. Using a constructivist grounded theory approach, we conducted thirteen in-depth interviews to examine how these individuals negotiate the constraints of their condition, integrate the illness into their identity, and use sport as a space for resilience, transformation, and advocacy.

Our findings reveal how ultra-endurance practices, far from being a barrier, can become a driver of personal growth and social visibility. The study highlights the importance of recognizing experiential knowledge in chronic disease management and calls for more inclusive, patient-centered approaches in healthcare and research.

We believe this manuscript is well-suited for *PLOS ONE* due to its interdisciplinary relevance, methodological rigor, and potential to inform clinical practice, health policy, and patient education. The study is reported in accordance with COREQ guidelines, and we have included the COREQ checklist and the codebook as Supporting Information to ensure transparency.

This manuscript has not been published elsewhere and is not under consideration by another journal. All authors have approved the final version and declare no conflicts of interest.

We thank you for considering our work and look forward to your feedback.

Sincerely,
Dr. Jean-Charles Vauthier
(on behalf of all co-authors)
Dr. Jean-Charles Vauthier
Université de Lorraine
Département de médecine générale
9 avenue de la forêt de Haye
54500 Vandoeuvre-lès-Nancy, France
jean-charles.vauthier@univ-lorraine.fr
+33 6 87 70 16 21

Cover Letter – Revised Submission

Dear Editor,

Thank you for the opportunity to revise and resubmit our manuscript entitled "*Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance*" (Manuscript ID: PONE-D-25-52862). We greatly appreciate the constructive feedback provided by the reviewers and have carefully addressed all comments to improve the clarity, rigor, and relevance of the paper.

Summary of Revisions

*   **Title and Formatting:** The title has been revised for precision and compliance with PLOS ONE style. Affiliations and formatting have been checked according to journal guidelines.

*   **Ethics and Data Availability:** The ethics statement now appears only in the Methods section. The Data Availability statement has been updated with an institutional contact (Université de Lorraine Data Access Committee).

*   **Participant Table:** Expanded to include age, sex, diabetes duration, technology use, and type of race, while preserving anonymity and respecting ethical constraints.

*   **References:** Verified for accuracy and completeness. Integrated the concept of *supercrip narratives* through Williams et al. (2021), as suggested by reviewers.

*   **Sample Justification:** Added explanation regarding sample size and gender distribution, highlighting its alignment with qualitative standards and the rarity of the target population.

*   **Reflexivity:** Strengthened discussion of the principal investigator's dual role (physician and person living with T1D) and strategies to minimize bias (reflexive journaling, triangulation).

*   **Clinical Implications:** Added recommendations for endocrinologists and primary care physicians to support patients pursuing ultra-endurance goals through individualized guidance and collaborative care.

*   **Language and Style:** Revised several sentences for improved fluency and readability, following reviewer suggestions.

We believe these changes have significantly enhanced the manuscript and addressed all concerns raised during the review process. Thank you for considering this revised version for publication in PLOS ONE.

Sincerely,
Dr. Jean-Charles Vauthier
(on behalf of all co-authors)
1 Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance

2 *Living with T1D in Ultra-Endurance*

3 Authors:

4 Jean-Charles Vauthier, MD¹,²,³

5 Lucie Choley²

6 Bernard Kabuth, PhD¹,³

7

8 Author Affiliations:

9 ¹ Université de Lorraine (France)

10 ² Département de médecine Générale, Faculté de médecine, Nancy, France

11 ³ InterPSY UR 4432, Université de Lorraine, Nancy, France

12 Corresponding Author:

13 Dr. Jean-Charles Vauthier

14 Email: jean-charles.vauthier@univ-lorraine.fr

15 Word Count: 3524 words

16 Number of Tables/Figures:

17 Figures: 1

18 Conflict of Interest Statement:

19 The authors declare no conflicts of interest relevant to this manuscript.

20 Funding:

21 The authors received no specific funding for this work.
22 Data Availability Statement:

23 All relevant data are included within the manuscript and its Supporting Information files. De-
24 identified interview transcripts can be made available upon reasonable request, subject to
25 ethical guidelines and participant consent. Requests should be directed to the institutional
26 Data Access Committee of Université de Lorraine (dpo-contact@univ-lorraine.fr).

27 Author Contributions:

28 JCV designed the research protocol, recruited participants, conducted and transcribed
29 interviews, and participated in analysis and writing.

30 LC, and BK participated in the analysis of the transcripts and contributed to writing and revising the manuscript.

32 All authors approved the final version of the manuscript.

33

34 Abstract:

35 Background

36 This study explores how people with type 1 diabetes experience ultra-endurance sports,
37 focusing on identity, self-management, and psychosocial impacts through a qualitative
38 approach.

39 Methods and findings

40 This qualitative study used a constructivist grounded theory approach. Thirteen semi-
41 structured interviews were conducted with French-speaking adults living with T1D who had
42 completed at least one marathon or ultra-endurance race. Data were analyzed inductively
43 through line-by-line coding, focused coding, and thematic categorization, supported by
44 NVivo® software and reported in accordance with COREQ guidelines.
45 Four major themes emerged: (1) a progressive process of acceptance, from the shock of
46 diagnosis to identity integration; (2) the ambivalence of being “ill,” with tensions between
47 medical status and personal identity; (3) the mental load of diabetes management, intensified
48 by ultra-endurance but mitigated by adaptive strategies and peer support; and (4) sport as a
49 transformative space for self-affirmation, resilience, and advocacy. Participants described
50 how ultra-endurance helped them reclaim agency, reframe their illness, and inspire others.

51 Conclusions

52 Ultra-endurance sports offer a unique context for identity reconstruction and empowerment
53 among people with T1D. Far from being a barrier, the illness can become a driver of personal
54 growth and social visibility. These findings highlight the importance of recognizing
55 experiential knowledge in chronic disease management and call for more inclusive, patient-
56 centered approaches in healthcare and research.
## 57 Introduction

Type 1 diabetes (T1D) is a chronic autoimmune condition that requires continuous self-management, including insulin therapy, blood glucose monitoring, dietary regulation, and physical activity. This constant vigilance imposes a significant mental and emotional burden, particularly among young adults, and can affect psychological well-being, quality of life, and identity development (1–3).

While moderate physical activity is widely recommended in T1D management, the lived experience of individuals engaging in extreme physical challenges—such as ultra-endurance sports—remains underexplored. Ultra-endurance events, lasting hours or even days, create unique physical and psychological challenges. For individuals with T1D, these challenges include anticipating energy needs, adjusting insulin regimens in real time, and managing the risks of hypo- or hyperglycemia (4).

Existing literature on T1D and exercise has primarily focused on physiological outcomes, therapeutic adjustments, and metabolic benefits (5,6). However, qualitative studies that explore the subjective experience of living with T1D in high-performance contexts are scarce. The few available studies suggest that sport can serve as a powerful medium for identity reconstruction, allowing individuals to shift from a “sick” identity to that of an “athlete” or “role model” (7,8).

Moreover, recent reviews have highlighted a lack of patient involvement in research on T1D and exercise, and a limited focus on experiential dimensions such as autonomy, emotional well-being, and self-perception (6). These gaps are most evident where illness meets expectations of performance, self-transcendence, and visibility.

This study aims to explore the lived experience of individuals with T1D who engage in ultra-endurance sports. Using a qualitative approach grounded in constructivist grounded theory,
81 we examine how these individuals negotiate the constraints of their condition, integrate the
82 illness into their identity, and use sport as a space for resilience, transformation, and
83 recognition. By centering the voices of patients, this research contributes to a more nuanced
84 understanding of chronic illness in extreme contexts and invites a rethinking of the
85 boundaries between health, performance, and vulnerability.

86 This study is part of a broader qualitative research project exploring the lived experience of
87 individuals with type 1 diabetes in the context of endurance sports. While the present article
88 focuses on individual trajectories and identity negotiation in ultra-endurance, other
89 components of the project address complementary dimensions such as peer communities,
90 patient-physician relationships, and the role of self-monitoring technologies. By centering the
91 voices of patients, this study contributes to a more nuanced understanding of chronic illness
92 in extreme contexts and invites a rethinking of the boundaries between health, performance,
93 and vulnerability.

94
95 **Materials and Methods**

96 *Study Design*

97 This study employed a qualitative design based on constructivist grounded theory, as
98 developed by Charmaz (9). This approach is particularly suited to exploring complex,
99 subjective experiences and allows for the co-construction of meaning between researchers
100 and participants.

101 To clarify the epistemological positioning and ensure methodological coherence, we also
102 drew on Rieger's typology of grounded theory approaches, which distinguishes between
103 objectivist, constructivist, and postmodern variants (10). Our study aligns with the
104 constructivist tradition, emphasizing reflexivity, contextual interpretation, and the co-
105 production of knowledge.

106 The study followed the COREQ (Consolidated Criteria for Reporting Qualitative Research) guidelines to ensure transparency and rigor (see Supporting Information). The aim was to
107 generate theoretical insights into how individuals living with type 1 diabetes (T1D)
108 experience and manage their condition in the context of ultra-endurance sports.

110 *Researcher Positioning*

111 The principal investigator (JCV) occupies a dual position as both a healthcare professional
112 and a person living with type 1 diabetes. This insider status facilitated access to participants
113 and enabled nuanced understanding of their experiences. However, it also raised potential
114 risks of interpretive bias and over-identification. To mitigate these risks, several strategies
115 were implemented: maintaining a reflexive journal throughout data collection and analysis;
116 systematically documenting emotional responses and methodological decisions; and engaging
117 in regular debriefing sessions with co-authors who did not share the same experiential
background. These measures aimed to ensure critical distance and enhance the credibility of
the findings.

A reflexive journal was maintained throughout the research process to document
methodological decisions, emotional responses, and evolving interpretations. This practice
aligns with current recommendations for enhancing transparency and reflexivity in qualitative
research (11).

Regular discussions with the research team (LC and BK), who did not share the same
experiential background, contributed to analytical triangulation and helped ensure critical
distance. This reflexive stance aligns with the constructivist grounded theory approach
adopted in this study, which acknowledges the co-construction of meaning between
researcher and participants.

129 *Sampling and Recruitment*

Participants were recruited using purposive sampling to ensure the inclusion of individuals
with relevant experience. Eligibility criteria were: (I) age 18 or older; (II) living with type 1
diabetes; (III) having completed at least one marathon or ultra-endurance race (road or trail)
in the past five years; and (IV) fluency in French and ability to provide informed consent.

Recruitment was conducted between July 4, 2024 and December 19, 2024, through diabetes
peer-support groups, social media platforms, and word-of-mouth. The final sample consisted
of 13 participants (11 men and 2 women), aged 26 to 66 years, with a mean diabetes duration
of 18.7 years.

Sampling was adjusted iteratively during data collection and analysis, following the
principles of theoretical sampling. Recruitment ceased when interpretive saturation was
reached—that is, when no new conceptual insights emerged from additional interviews.
141 All participants provided written informed consent, signed in two copies: one retained by the
142 participant and one by the researcher. The study was approved by the South-East VI Research
143 Ethics Committee (Reference: 24.00907.000253).

144 *Data Collection*

145 Data were collected through semi-structured interviews conducted via videoconference
146 between July and December 2024. All interviews were conducted by the principal
147 investigator (JCV), who shared experiential proximity with participants. Interviews were
148 audio-recorded with consent and fully transcribed verbatim. Transcripts were enriched with
149 contextual notes and non-verbal cues when relevant.

150 The interview guide was developed based on a review of the literature and refined iteratively
151 during the study. It included open-ended questions exploring diagnosis, daily management,
152 emotional and social experiences, and the role of sport in identity and self-perception.

153 Interviews lasted between 47 and 68 minutes (mean: 57 minutes). Audio files were deleted
154 after transcription, in accordance with ethical requirements. All data were anonymized and
155 securely stored.

156 Field notes and reflexive memos were written after each interview to capture impressions,
157 emerging themes, and methodological reflections.

158 *Data Analysis*

159 Data were analyzed using constructivist grounded theory, following the procedures outlined
160 by Charmaz (9). The analysis involved several iterative steps: (I) line-by-line initial coding of
161 transcripts; (II) focused coding to identify recurring patterns; (III) development of conceptual
162 categories; and (IV) integration of themes through constant comparison.
163 Analytical memos were written throughout the process to document emerging insights, theoretical reflections, and methodological decisions. Coding and data organization were supported by NVivo® software (version 1.7.2).

166 The research team engaged in regular discussions to refine categories and ensure analytical coherence. Triangulation was achieved through collaborative interpretation among the three authors, who brought complementary perspectives to the analysis.

169 Sampling and analysis were conducted in parallel, and recruitment was stopped when interpretive saturation was reached—that is, when no new conceptual insights emerged from additional data (12,13).

172 The analysis emphasized reflexivity, contextual interpretation, and the co-construction of meaning, in line with the constructivist epistemology of the study.

174 *Ethical Considerations*

175 This study was approved by the South-East VI Research Ethics Committee (Reference: 24.00907.000253) on April 5, 2024. All participants received detailed information about the study's objectives, procedures, and confidentiality measures, and provided written informed consent prior to participation.

179 Participants were informed of their right to withdraw at any time without consequence. Data were anonymized during transcription, and all identifying information was removed. Audio recordings were deleted after transcription, and all data were securely stored in accordance with institutional and ethical guidelines.

183 The study adhered to the ethical principles outlined in the Declaration of Helsinki and followed best practices for qualitative research involving human participants.

185
186 **Results**

187 *Participant Characteristics and Study Overview*

188 Thirteen interviews were conducted between July and December 2024 with individuals living
189 with type 1 diabetes and engaged in endurance or ultra-endurance sports. Participants (coded
190 S1 to S13) varied in age, diabetes duration, and athletic background. Most were men (n = 11),
191 with a mean age of 42.8 years (SD = 10.8) and a mean diabetes duration of 18.7 years (SD =
192 9.8). All had completed at least one marathon or ultra-endurance race in the past five years.

193 Interviews lasted between 47 and 68 minutes (mean: 57 minutes). Detailed participant
194 characteristics are presented in Table 1.

195 Table 1: table of participants

196 *Analytical Approach*

197 Thematic analysis followed the principles of constructivist grounded theory. After line-by-
198 line initial coding, focused coding was used to group significant segments into emerging
199 categories. Analytical memos were written throughout the process to support theoretical
200 development. NVivo® software (v1.7.2) was used to facilitate coding and data organization.

201 The research team engaged in regular discussions to refine categories and ensure analytical
202 coherence. Triangulation was achieved through collaborative interpretation among the three
203 authors. Sampling and analysis were conducted in parallel, and recruitment was stopped
204 when interpretive saturation was reached.

205 *From Shock to Meaning: The Journey Toward Acceptance*

206 The diagnosis of type 1 diabetes is often experienced as a brutal biographical rupture, an
207 existential shock. Several runners described initial reactions of disbelief, fear, or denial:
208 "I was devastated [...] I thought: 'This is my last pancake.'" (S5)

209 "When I found out, I reacted very badly. I didn't want to change anything in my life." (S5)

210 For others, the diagnosis coincided with other destabilizing events, such as the COVID-19 lockdown:

212 "I got the news on Friday, right before the first lockdown. On Monday, I was hospitalized, then sent home alone with my pens and test strips." (S9)

214 Some testimonies reflect a sudden awareness of the disease's severity, sometimes through critical episodes:

216 "I lost consciousness, convulsed, my friends held me down... I woke up in a helicopter." (S3)

217 The shock also stems from dietary constraints or negative social representations:

218 "I enjoy eating, enjoying life... And then they talk to me about dieting. I said: 'No way! I'll adapt my insulin to my life, not the other way around.'" (S4)

220 Others describe a gentler entry into the disease, facilitated by family support:

221 "I was lucky to have a mother who's a nurse. She let me manage it from the start." (S8)

222 Identity Disruption and the Ambivalence of Being "Ill"

223 This theme reveals a strong identity tension. While the medical reality of the disease is undeniable, its integration into personal identity is far from straightforward.

225 Some acknowledge their status as ill, linked to insulin dependence:

226 "I don't consider myself sick, but I am. We inject a product every day, and if we don't, we die." (S9)

228 Others reject the label or seek to distance themselves from the social image of illness:
229 "I'm not sick. I'm diabetic, that's all!" (S7)

230 "I've never considered myself sick. I don't like the word 'sick,' just like I don't like

231 'patient.'" (S13)

232 The distinction between "having a disease" and "being sick" is recurrent:

233 "I don't feel sick. I have a system." (S11)

234 "When I'm exercising, I don't feel sick. But for insurance companies, I am." (S5)

235 This ambivalence is sometimes expressed with humor or irony, as a way to reclaim self-definition:

237 "Diabetic but not sick!" (S13)

238 Mental Load and Adaptation Strategies

239 The mental load associated with T1D is omnipresent in the runners' narratives. It manifests
240 as constant vigilance, anticipation, and psychological fatigue.

241 A Constant Presence

242 Diabetes requires continuous attention, from waking to bedtime. One participant compares it
to an extra child:

244 "It's like a third child, always there, always, always." (S9)

245 Monitoring, insulin adjustments, and dietary management become daily reflexes:

246 "You think about it all the time, you check your numbers, your scores." (S1)

247 Sport-Specific Anticipation and Logistics

248 Ultra-endurance adds another layer of complexity. Each outing requires meticulous
249 preparation:
250 "Even for a short run, I check beforehand, adjust the pump rate, take a fruit paste." (S8)

251 Psychological and Social Consequences

252 This constant vigilance leads to exhaustion and affects spontaneity and social life:

253 "The mental load is the biggest obstacle." (S2)

254 "Spontaneously grabbing your shoes and going out? That's no longer possible." (S12)

255 Technologies: Relief or Overload?

256 Technological aids offer control but can also increase mental load:

257 "Before, I checked 6 to 8 times a day. Now I check constantly." (S10)

258 Some even revert to simpler systems:

259 "I stopped using the closed loop. It was an extra mental burden." (S13)

260 Sport as a Lever for Transformation and Assertion

261 For many runners, sport is not just a health activity—it's a space for self-affirmation, resilience, and identity reconstruction.

263 "I don't do it to prove anything to others, but to prove to myself that it's possible." (S2)

264 Visibility and Advocacy

265 Running becomes a space of visibility and sometimes activism:

266 "It's important to show that the disease doesn't stop us." (S5)

267 Inspiration and Social Role

268 Some runners take on a role model status, especially for young diabetics:

269 "Parents told me it reassured them to see that it's possible." (S6)
270 Self-Management Skills and Learning

271 Ultra-endurance requires deep knowledge of one's body and diabetes. Strategies are highly

272 personalized and often learned through trial and error:

273 "It took me four years to find balance." (S1)

274 Reversing the Meaning of Illness

275 For several runners, the disease paradoxically becomes a source of strength:

276 "My diabetes helped me strengthen my mental resilience." (S1)

277
278 **Discussion**

279 *Contextualizing the results*

280 This study highlights the complexity of living with type 1 diabetes (T1D) in the context of
281 ultra-endurance sports. The diagnosis was frequently described as a biographical rupture,
282 echoing Bury's concept of *biographical disruption* (14), where illness interrupts the
283 continuity of identity and life trajectory. Participants' narratives also resonate with Claire
284 Marin's reflections on illness as an existential fracture that forces a redefinition of self and
285 relationships (15).

286 Beyond the initial shock, the process of acceptance emerged as dynamic and multifaceted. It
287 involved not only medical adaptation but also identity negotiation, emotional regulation, and
288 social positioning. This aligns with Havi Carel's phenomenological perspective, which
289 frames illness as a transformation of bodily experience and a potential source of reflective
290 awareness (16)

291 The findings support previous research suggesting that acceptance of chronic illness is
292 associated with improved emotional and social well-being (17), and with a sense of harmony
293 with oneself (18). In this study, acceptance was often facilitated by sport, peer support, and
294 self-management strategies, reflecting a broader psychosocial adaptation process (19).

295 Participants' ambivalence about being "ill" or "sick" shows the tension between medical
296 labels and personal identity. This perspective resonates with recent work on narrative
297 imagination and disability, which highlights the prevalence of 'supercrip' narratives and their
298 implications for inclusion (20). This echoes the work of Bright and Molnár (7), who showed
299 how individuals with T1D use sport to renegotiate identity and resist stigmatization. The
300 narratives collected here further demonstrate how ultra-endurance can serve as a space for
301 reclaiming agency, reframing illness, and asserting a positive self-image.
302 *Specificities of Ultra-Endurance*

303 Ultra-endurance sports represent a particularly demanding context for individuals living with
type 1 diabetes. The physical and psychological challenges inherent to these practices
304 intensify the mental load associated with diabetes management, requiring precise
305 anticipation, continuous adaptation, and deep metabolic knowledge. These observations are
306 consistent with broader research on ultra-endurance athletes, which highlights unique
307 physiological demands and motivational profiles in extreme sports contexts (21). Yet,
308 paradoxically, this extreme context also offers a space of freedom, glycemic stability, and
309 self-valorization.
310

311 Participants in this study described how ultra-endurance helped them develop advanced self-management skills, often acquired through trial and error and shared within peer communities. These findings align with Paley and Johnson's review (22), which identifies 312 resilience strategies among ultra-endurance athletes—such as acceptance, emotional 313 regulation, and positive reframing—that closely resemble those used by individuals 314 managing chronic illness. 315

317 The narratives collected also illustrate how sport can serve as a medium for identity
318 reconfiguration. Illness, rather than being solely a constraint, becomes a driver of self-
319 transcendence and social visibility. This inversion of stigma is particularly evident in the way
320 participants claim their condition, make it visible, and use it to inspire others. Pereira Vargas
321 et al. (8) have shown that athletes can construct authentic identities by embracing
322 vulnerability, provided they retain control over the narrative.

323 These findings add to the growing literature on how chronic illness intersects with
324 performance and identity. They suggest that ultra-endurance is not merely a physical
challenge, but a symbolic space where individuals negotiate autonomy, resilience, and
recognition.

While the benefits of ultra-endurance practices are evident in terms of identity reconstruction
and self-management, it is important to acknowledge that such extreme engagement may also
carry risks. Previous research has highlighted potential issues such as physical overload,
disordered eating, and exercise dependence among ultra-endurance athletes (23). Although
these aspects were not the focus of the present study, they warrant further investigation in
future research.

### *Strengths and Limitations*

This study provides rich insights into the lived experience of individuals with type 1 diabetes
engaged in ultra-endurance sports. Its strength lies in the depth of the qualitative data, the
reflexive positioning of the researcher, and the use of constructivist grounded theory to
capture complex identity dynamics.

However, several limitations must be acknowledged. First, the sample size was small (n = 13) and composed of highly engaged athletes, which limits the generalizability of the findings.
Although qualitative research does not seek statistical representativeness, the sample's homogeneity—especially in athletic commitment and peer-support involvement—may have amplified empowering narratives. Nevertheless, this size is consistent with qualitative standards and reflects the rarity of the target population: individuals living with type 1 diabetes and engaged in ultra-endurance sports are estimated to be fewer than one hundred in France. The gender imbalance (11 men, 2 women) mirrors the reality of ultra-endurance participation, where women typically represent 15–25% of athletes. While this composition limits transferability to other contexts, it remains coherent with the population studied and allowed for rich, diverse narratives.
Finally, the dual role of the principal investigator as both a healthcare professional and a person living with type 1 diabetes may have influenced data collection and interpretation.

While this insider position facilitated access and enriched understanding, it also raised potential risks of bias. Reflexive strategies—including maintaining a reflexive journal and engaging in regular debriefing with co-authors—were implemented to mitigate these risks and enhance credibility.

Second, recruitment through social media and peer networks may have introduced a selection bias, privileging participants already attuned to discourses of performance, autonomy, and resilience. This may have overshadowed more ambivalent or painful experiences, as documented in chronic illness research (24).

Third, the absence of comparison with other profiles of individuals living with T1D—such as non-athletes, those practicing other types of physical activity, or individuals in precarious social or medical situations—limits the scope of the conclusions. A comparative or longitudinal design could help refine the understanding of identity trajectories and adaptation strategies across diverse contexts.

Finally, the dual role of the principal investigator as both researcher and participant (living with T1D and practicing ultra-endurance) may have influenced data collection and interpretation. Although reflexive strategies were employed to mitigate this risk, including journaling and team triangulation, this insider position remains a methodological consideration.

## *Practical Implications*

The findings of this study underscore the importance of recognizing the experiential knowledge developed by individuals living with type 1 diabetes, particularly those engaged in ultra-endurance sports. These individuals demonstrate advanced self-management skills,
including anticipatory regulation, emotional coping, and personalized adaptation strategies.

Such expertise, often acquired outside formal healthcare settings, represents a valuable resource for improving therapeutic adherence and patient empowerment (25,26).

For healthcare professionals, these insights call for a shift from a strictly biomedical model toward a more collaborative and patient-centered approach. This includes acknowledging patients as active partners in care, integrating their lived experience into clinical decision-making, and supporting autonomy through tailored education and dialogue (27).

Patient education programs (PEPs) should incorporate psychosocial dimensions, cultural sensitivity, and experiential learning. Several authors have emphasized the need for tailored therapeutic approaches that reflect patients' lived realities and self-management strategies (28). The WHO recommends strengthening such programs to meet the challenges of chronic disease management, especially in contexts where patients must navigate their condition independently (29).

From a health policy perspective, the study highlights the structuring role of peer communities and physical activity in illness acceptance and identity reconstruction. These levers deserve institutional support through inclusive sports initiatives, urban planning that facilitates movement, and recognition of patient associations as legitimate actors in care governance (30–34).

Endocrinologists and general practitioners should actively discuss patients' ultra-endurance goals and offer tailored advice on insulin, nutrition, and risk management. Rather than discouraging such projects, clinicians can support safe participation by integrating experiential knowledge into therapeutic planning and fostering shared decision-making. General practitioners, who often maintain long-term relationships with patients, are ideally
396 positioned to coordinate care, monitor overall health, and facilitate dialogue between
397 specialists and patients pursuing extreme physical challenges.

398 *Future Research Directions*

399 This study sheds light on an underexplored area: the subjective experience of chronic illness
400 in the context of extreme sports. It invites further investigation into the intersections between
401 ultra-endurance, identity, and self-management in type 1 diabetes.

402 Future research could adopt comparative designs, including individuals with T1D who
403 engage in other forms of physical activity or those who do not practice sport, to better
404 understand the diversity of adaptation trajectories. Studies involving non-athletic or socially
405 vulnerable populations would help balance the empowering narratives observed here and
406 reveal other forms of coping or constraint.

407 Longitudinal approaches would also be valuable to explore how illness identity evolves over
time, in relation to life events, disease progression, and changing social contexts. Shneider et
408 al.(3) have shown that illness identity is dynamic and closely linked to therapeutic adherence
409 and health outcomes.

411 Finally, further research could examine the role of technological tools, peer communities, and
412 healthcare relationships in shaping the experience of chronic illness. These dimensions,
413 addressed in other components of the broader research project, deserve dedicated exploration
414 to inform more inclusive and participatory models of care.

415
416 **Conclusion**

417 This qualitative study, grounded in constructivist grounded theory and reported in accordance
418 with COREQ guidelines, explored the lived experience of individuals with type 1 diabetes
419 engaged in ultra-endurance sports. Through in-depth interviews and rigorous thematic
420 analysis, the study revealed how illness, initially experienced as a biographical rupture, can
421 become a space for adaptation, identity reconstruction, and resilience.

422 Ultra-endurance practices, while demanding, offer opportunities for self-reappropriation,
423 social visibility, and advocacy. Participants developed advanced self-management strategies
424 and reframed their condition as a source of strength rather than limitation.

425 The methodological approach—combining reflexive positioning, triangulation, and
426 interpretive saturation—ensured analytical depth and credibility. While the findings are not
427 statistically generalizable, they provide transferable insights into the psychosocial dynamics
428 of chronic illness in performance-oriented contexts.

429 These results invite a rethinking of support models for chronic illness, emphasizing
430 experiential knowledge, patient autonomy, and the role of peer communities. They also
431 highlight the need for inclusive healthcare approaches that recognize diverse trajectories and
432 forms of bodily engagement.

433 Ultimately, living with type 1 diabetes in ultra-endurance is not only about coping—it is
434 about transforming the illness into a driver for going further, higher, stronger—differently.

435

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<table><caption>Table 1. Characteristics of study participants</caption><thead><tr><th>ID</th><th>Sex</th><th>Age</th><th>Age at diagnosis</th><th>Duration of T1D</th><th>Treatment</th><th>CGM</th><th>HbA1c</th><th>Sports practiced</th><th>Max distance</th></tr></thead><tbody><tr><td>S1</td><td>M</td><td>36</td><td>21</td><td>15</td><td>Pump (Omnipod)</td><td>Dexcom</td><td>7.8</td><td>Ultra-trail, ski, tennis-marathon</td><td>200 km</td></tr><tr><td>S2</td><td>M</td><td>26</td><td>15</td><td>11</td><td>MDI (pens)</td><td>Libre 2</td><td>N/A</td><td>Trail, triathlon, rugby-marathon</td><td>80 km</td></tr><tr><td>S3</td><td>M</td><td>53</td><td>38</td><td>15</td><td>Pump (Omnipod Dash)</td><td>Dexcom</td><td>N/A</td><td>Ultra-trail-marathon</td><td>108 km</td></tr><tr><td>S4</td><td>M</td><td>48</td><td>25</td><td>23</td><td>Pump (Omnipod, Diabeloop planned)</td><td>Dexcom G6</td><td>7.4</td><td>Trail, marathon</td><td>59 km</td></tr><tr><td>S5</td><td>F</td><td>49</td><td>23</td><td>27</td><td>Pump</td><td>Dexcom</td><td>5.8</td><td>Trail, ultra cycling, Marathon, triathlon</td><td>42 km</td></tr><tr><td>S6</td><td>M</td><td>41</td><td>19</td><td>22</td><td>Pump</td><td>Dexcom</td><td>N/A</td><td>Trail-marathon</td><td>50 km</td></tr><tr><td>S7</td><td>M</td><td>66</td><td>40</td><td>26</td><td>MDI (pens)</td><td>Libre</td><td>6.7</td><td>Trail-marathon</td><td>50 km</td></tr><tr><td>S8</td><td>M</td><td>37</td><td>13</td><td>24</td><td>Pump</td><td>Dexcom</td><td>N/A</td><td>Trail-marathon</td><td>60 km</td></tr><tr><td>S9</td><td>M</td><td>46</td><td>42</td><td>4</td><td>MDI (pens)</td><td>Libre</td><td>N/A</td><td>Trail-marathon</td><td>42 km</td></tr><tr><td>S10</td><td>M</td><td>38</td><td>10</td><td>28</td><td>Pump</td><td>Dexcom</td><td>6.4-6.5</td><td>Trail-marathon</td><td>100 km</td></tr><tr><td>S11</td><td>M</td><td>44</td><td>19</td><td>25</td><td>Pump</td><td>Dexcom</td><td>6-6.2</td><td>Trail-marathon</td><td>80 km</td></tr><tr><td>S12</td><td>M</td><td>26</td><td>23</td><td>3</td><td>MDI (pens)</td><td>Libre</td><td>N/A</td><td>Trail-marathon</td><td>42 km</td></tr><tr><td>S13</td><td>F</td><td>46</td><td>16</td><td>30</td><td>Pump</td><td>Dexcom</td><td>N/A</td><td>Trail-marathon</td><td>50 km</td></tr></tbody></table>

550

This table summarizes demographic and clinical characteristics of participants, including age,

diabetes duration, treatment type, technology use, and athletic background. HbA1c values were

not systematically collected; they are reported only when spontaneously mentioned by
554 participants during interviews, in accordance with the protocol approved by the ethics

555 committee.

556

557
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AU 1938 - 24.00907.000253 - Avis favorable.pdf
1 Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance

2 *Living with T1D in Ultra-Endurance*

3 Authors:

4 Jean-Charles Vauthier, MD¹,²,³

5 Lucie Choley²

6 Bernard Kabuth, PhD¹,³

7

8 Author Affiliations:

9 ¹ Université de Lorraine (France)

10 ² Département de médecine Générale, Faculté de médecine, Nancy, France

11 ³ InterPSY UR 4432, Université de Lorraine, Nancy, France

12 Corresponding Author:

13 Dr. Jean-Charles Vauthier

14 Email: jean-charles.vauthier@univ-lorraine.fr

15 Postal Address: 9 av de la forêt de Haye, F54500 VANDOEUVRE LES NANCY

16 Phone: +33687701621

17 Word Count: 3524 words

18 Number of Tables/Figures:

19 Figures: 1

20 Conflict of Interest Statement:

21 The authors declare no conflicts of interest relevant to this manuscript.
22 Funding:

23 This research received no specific grant from any funding agency in the public, commercial,

24 or not-for-profit sectors.

25 The authors received no specific funding for this work.

26 Ethical Approval:

27 This study was approved by the South-East VI Research Ethics Committee (Reference:

28 24.00907.000253) on April 5, 2024.

29 Data Availability Statement:

30 Interview transcripts are available from the corresponding author upon reasonable request.

31 All relevant data are included within the manuscript and its Supporting Information files. De-

32 identified interview transcripts can be made available upon reasonable request, subject to

33 ethical guidelines and participant consent. Requests should be directed to the institutional

34 Data Access Committee of Université de Lorraine (dpo-contact@univ-lorraine.fr).

35 Author Contributions:

36 JCV designed the research protocol, recruited participants, conducted and transcribed

37 interviews, and participated in analysis and writing.

38 LC, and BK participated in the analysis of the transcripts and contributed to writing and

39 revising the manuscript.

40 All authors approved the final version of the manuscript.

41

42 Abstract:
43 Background

44 To explore the subjective experience of living with type 1 diabetes (T1D) among individuals
45 engaged in ultra-endurance sports, using a qualitative approach to focus on identity, self-
46 management, and the psychosocial impact of extreme physical activity.

47 This study explores how people with type 1 diabetes experience ultra-endurance sports,
48 focusing on identity, self-management, and psychosocial impacts through a qualitative
49 approach.

50 Methods and findings

51 This qualitative study used a constructivist grounded theory approach. Thirteen semi-
52 structured interviews were conducted with French-speaking adults living with T1D who had
53 completed at least one marathon or ultra-endurance race. Data were analyzed inductively
54 through line-by-line coding, focused coding, and thematic categorization, supported by
55 NVivo® software and reported in accordance with COREQ guidelines.

56 Four major themes emerged: (1) a progressive process of acceptance, from the shock of
57 diagnosis to identity integration; (2) the ambivalence of being “ill,” with tensions between
58 medical status and personal identity; (3) the mental load of diabetes management, intensified
59 by ultra-endurance but mitigated by adaptive strategies and peer support; and (4) sport as a
60 transformative space for self-affirmation, resilience, and advocacy. Participants described
61 how ultra-endurance helped them reclaim agency, reframe their illness, and inspire others.

62 Conclusions

63 Ultra-endurance sports offer a unique context for identity reconstruction and empowerment
64 among people with T1D. Far from being a barrier, the illness can become a driver of personal
65 growth and social visibility. These findings highlight the importance of recognizing
66 experiential knowledge in chronic disease management and call for more inclusive, patient-

67 centered approaches in healthcare and research.
68 **Introduction**

69 Type 1 diabetes (T1D) is a chronic autoimmune condition that requires continuous self-
70 management, including insulin therapy, blood glucose monitoring, dietary regulation, and
71 physical activity. This constant vigilance imposes a significant mental and emotional burden,
72 particularly among young adults, and can affect psychological well-being, quality of life, and
73 identity development (1–3).

74 While moderate physical activity is widely recommended in T1D management, the lived
75 experience of individuals engaging in extreme physical challenges—such as ultra-endurance
76 sports—remains underexplored. Ultra-endurance events, which span several hours to days
77 and often take place in natural environments, pose unique physiological and psychological
demands. Ultra-endurance events, lasting hours or even days, create unique physical and
78 psychological challenges. For individuals with T1D, these challenges include anticipating
79 energy needs, adjusting insulin regimens in real time, and managing the risks of hypo- or
80 energy needs, adjusting insulin regimens in real time, and managing the risks of hypo- or
81 hyperglycemia (4).

82 Existing literature on T1D and exercise has primarily focused on physiological outcomes,
83 therapeutic adjustments, and metabolic benefits (5,6). However, qualitative studies that
84 explore the subjective experience of living with T1D in high-performance contexts are
85 scarce. The few available studies suggest that sport can serve as a powerful medium for
86 identity reconstruction, allowing individuals to shift from a “sick” identity to that of an
87 “athlete” or “role model” (7,8).

88 Moreover, recent reviews have highlighted a lack of patient involvement in research on T1D
89 and exercise, and a limited focus on experiential dimensions such as autonomy, emotional
90 well-being, and self-perception (6). These gaps are particularly salient in contexts where
91 illness intersects with norms of performance, self-transcendence, and social visibility. These
92 gaps are most evident where illness meets expectations of performance, self-transcendence,
93 and visibility.

94 This study aims to explore the lived experience of individuals with T1D who engage in ultra-
95 endurance sports. Using a qualitative approach grounded in constructivist grounded theory,
96 we examine how these individuals negotiate the constraints of their condition, integrate the
97 illness into their identity, and use sport as a space for resilience, transformation, and
98 recognition. By centering the voices of patients, this research contributes to a more nuanced
99 understanding of chronic illness in extreme contexts and invites a rethinking of the
100 boundaries between health, performance, and vulnerability.

101 This study is part of a broader qualitative research project exploring the lived experience of
102 individuals with type 1 diabetes in the context of endurance sports. While the present article
103 focuses on individual trajectories and identity negotiation in ultra-endurance, other
104 components of the project address complementary dimensions such as peer communities,
105 patient-physician relationships, and the role of self-monitoring technologies. By centering the
106 voices of patients, this study contributes to a more nuanced understanding of chronic illness
107 in extreme contexts and invites a rethinking of the boundaries between health, performance,
108 and vulnerability.

109
110 **Materials and Methods**

111 *Study Design*

112 This study employed a qualitative design based on constructivist grounded theory, as
113 developed by Charmaz (9) This approach is particularly suited to exploring complex,
114 subjective experiences and allows for the co-construction of meaning between researchers
115 and participants.

116 To clarify the epistemological positioning and ensure methodological coherence, we also
117 drew on Rieger's typology of grounded theory approaches, which distinguishes between
118 objectivist, constructivist, and postmodern variants (10). Our study aligns with the
119 constructivist tradition, emphasizing reflexivity, contextual interpretation, and the co-
120 production of knowledge.

121 The study followed the COREQ (Consolidated Criteria for Reporting Qualitative Research)
122 guidelines to ensure transparency and rigor (see Supporting Information). The aim was to
123 generate theoretical insights into how individuals living with type 1 diabetes (T1D)
124 experience and manage their condition in the context of ultra-endurance sports.

125 *Researcher Positioning*

126 The principal investigator (JCV) is a general practitioner, an ultra-endurance runner, and lives
127 with type 1 diabetes himself. This "insider" position facilitated access to the field and enabled
128 a nuanced understanding of the participants' experiences. However, it also required
129 continuous reflexive vigilance to mitigate potential biases.

130 The principal investigator (JCV) occupies a dual position as both a healthcare professional
131 and a person living with type 1 diabetes. This insider status facilitated access to participants
132 and enabled nuanced understanding of their experiences. However, it also raised potential
risks of interpretive bias and over-identification. To mitigate these risks, several strategies were implemented: maintaining a reflexive journal throughout data collection and analysis; systematically documenting emotional responses and methodological decisions; and engaging in regular debriefing sessions with co-authors who did not share the same experiential background. These measures aimed to ensure critical distance and enhance the credibility of the findings.

A reflexive journal was maintained throughout the research process to document methodological decisions, emotional responses, and evolving interpretations. This practice aligns with current recommendations for enhancing transparency and reflexivity in qualitative research (11).

Regular discussions with the research team (LC and BK), who did not share the same experiential background, contributed to analytical triangulation and helped ensure critical distance. This reflexive stance aligns with the constructivist grounded theory approach adopted in this study, which acknowledges the co-construction of meaning between researcher and participants.

## *Sampling and Recruitment*

Participants were recruited using purposive sampling to ensure the inclusion of individuals with relevant experience. Eligibility criteria were: (I) age 18 or older; (II) living with type 1 diabetes; (III) having completed at least one marathon or ultra-endurance race (road or trail) in the past five years; and (IV) fluency in French and ability to provide informed consent.

Recruitment was conducted between July 4, 2024 and December 19, 2024, through diabetes peer-support groups, social media platforms, and word-of-mouth. The final sample consisted
155 of 13 participants (11 men and 2 women), aged 26 to 66 years, with a mean diabetes duration
156 of 18.7 years.

157 Sampling was adjusted iteratively during data collection and analysis, following the
158 principles of theoretical sampling. Recruitment ceased when interpretive saturation was
159 reached—that is, when no new conceptual insights emerged from additional interviews.

160 All participants provided written informed consent, signed in two copies: one retained by the
161 participant and one by the researcher. The study was approved by the South-East VI Research
162 Ethics Committee (Reference: 24.00907.000253).

163 *Data Collection*

164 Data were collected through semi-structured interviews conducted via videoconference
165 between July and December 2024. All interviews were conducted by the principal
166 investigator (JCV), who shared experiential proximity with participants. Interviews were
167 audio-recorded with consent and fully transcribed verbatim. Transcripts were enriched with
168 contextual notes and non-verbal cues when relevant.

169 The interview guide was developed based on a review of the literature and refined iteratively
170 during the study. It included open-ended questions exploring diagnosis, daily management,
171 emotional and social experiences, and the role of sport in identity and self-perception. The
172 *guide is available as Supporting Information.*

173 Interviews lasted between 47 and 68 minutes (mean: 57 minutes). Audio files were deleted
174 after transcription, in accordance with ethical requirements. All data were anonymized and
175 securely stored.

176 Field notes and reflexive memos were written after each interview to capture impressions,
177 emerging themes, and methodological reflections.
178 *Data Analysis*

179 Data were analyzed using constructivist grounded theory, following the procedures outlined
180 by Charmaz (9). The analysis involved several iterative steps: (I) line-by-line initial coding of
181 transcripts; (II) focused coding to identify recurring patterns; (III) development of conceptual
182 categories; and (IV) integration of themes through constant comparison.

183 Analytical memos were written throughout the process to document emerging insights,
184 theoretical reflections, and methodological decisions. Coding and data organization were
185 supported by NVivo® software (version 1.7.2).

186 The research team engaged in regular discussions to refine categories and ensure analytical
187 coherence. Triangulation was achieved through collaborative interpretation among the three
188 authors, who brought complementary perspectives to the analysis.

189 Sampling and analysis were conducted in parallel, and recruitment was stopped when
190 interpretive saturation was reached—that is, when no new conceptual insights emerged from
191 additional data (12,13).

192 The analysis emphasized reflexivity, contextual interpretation, and the co-construction of
193 meaning, in line with the constructivist epistemology of the study.

194 *Ethical Considerations*

195 This study was approved by the South-East VI Research Ethics Committee (Reference:
196 24.00907.000253) on April 5, 2024. All participants received detailed information about the
197 study's objectives, procedures, and confidentiality measures, and provided written informed
198 consent prior to participation.

199 Participants were informed of their right to withdraw at any time without consequence. Data
200 were anonymized during transcription, and all identifying information was removed. Audio
201 recordings were deleted after transcription, and all data were securely stored in accordance

202 with institutional and ethical guidelines.

203 The study adhered to the ethical principles outlined in the Declaration of Helsinki and

204 followed best practices for qualitative research involving human participants.

205
206 **Results**

207 *Participant Characteristics and Study Overview*

208 Thirteen interviews were conducted between July and December 2024 with individuals living
209 with type 1 diabetes and engaged in endurance or ultra-endurance sports. Participants (coded
210 S1 to S13) varied in age, diabetes duration, and athletic background. Most were men (n = 11),
211 with a mean age of 42.8 years (SD = 10.8) and a mean diabetes duration of 18.7 years (SD =
212 9.8). All had completed at least one marathon or ultra-endurance race in the past five years.
213 Interviews lasted between 47 and 68 minutes (mean: 57 minutes). **Detailed participant**
214 characteristics are presented in Table 1.

215 Table 1: table of participants

216 *Analytical Approach*

217 Thematic analysis followed the principles of constructivist grounded theory. After line-by-
218 line initial coding, focused coding was used to group significant segments into emerging
219 categories. Analytical memos were written throughout the process to support theoretical
220 development. NVivo® software (v1.7.2) was used to facilitate coding and data organization.

221 The research team engaged in regular discussions to refine categories and ensure analytical
222 coherence. Triangulation was achieved through collaborative interpretation among the three
223 authors. Sampling and analysis were conducted in parallel, and recruitment was stopped
224 when interpretive saturation was reached.

225 *From Shock to Meaning: The Journey Toward Acceptance*

226 The diagnosis of type 1 diabetes is often experienced as a brutal biographical rupture, an
227 existential shock. Several runners described initial reactions of disbelief, fear, or denial:
228 "I was devastated [...] I thought: 'This is my last pancake.'" (S5)

229 "When I found out, I reacted very badly. I didn't want to change anything in my life." (S5)

230 For others, the diagnosis coincided with other destabilizing events, such as the COVID-19 lockdown:

231 "I got the news on Friday, right before the first lockdown. On Monday, I was hospitalized, then sent home alone with my pens and test strips." (S9)

232 Some testimonies reflect a sudden awareness of the disease's severity, sometimes through critical episodes:

236 "I lost consciousness, convulsed, my friends held me down... I woke up in a helicopter." (S3)

237 The shock also stems from dietary constraints or negative social representations:

238 "I enjoy eating, enjoying life... And then they talk to me about dieting. I said: 'No way! I'll adapt my insulin to my life, not the other way around.'" (S4)

240 Others describe a gentler entry into the disease, facilitated by family support:

241 "I was lucky to have a mother who's a nurse. She let me manage it from the start." (S8)

242 Identity Disruption and the Ambivalence of Being "Ill"

243 This theme reveals a strong identity tension. While the medical reality of the disease is undeniable, its integration into personal identity is far from straightforward.

245 Some acknowledge their status as ill, linked to insulin dependence:

246 "I don't consider myself sick, but I am. We inject a product every day, and if we don't, we die." (S9)

248 Others reject the label or seek to distance themselves from the social image of illness:
249 "I'm not sick. I'm diabetic, that's all!" (S7)

250 "I've never considered myself sick. I don't like the word 'sick,' just like I don't like

251 'patient.'" (S13)

252 The distinction between "having a disease" and "being sick" is recurrent:

253 "I don't feel sick. I have a system." (S11)

254 "When I'm exercising, I don't feel sick. But for insurance companies, I am." (S5)

255 This ambivalence is sometimes expressed with humor or irony, as a way to reclaim self-definition:

257 "Diabetic but not sick!" (S13)

258 Mental Load and Adaptation Strategies

259 The mental load associated with T1D is omnipresent in the runners' narratives. It manifests
260 as constant vigilance, anticipation, and psychological fatigue.

261 A Constant Presence

262 Diabetes requires continuous attention, from waking to bedtime. One participant compares it
to an extra child:

264 "It's like a third child, always there, always, always." (S9)

265 Monitoring, insulin adjustments, and dietary management become daily reflexes:

266 "You think about it all the time, you check your numbers, your scores." (S1)

267 Sport-Specific Anticipation and Logistics

268 Ultra-endurance adds another layer of complexity. Each outing requires meticulous
269 preparation:
270 "Even for a short run, I check beforehand, adjust the pump rate, take a fruit paste." (S8)

271 Psychological and Social Consequences

272 This constant vigilance leads to exhaustion and affects spontaneity and social life:

273 "The mental load is the biggest obstacle." (S2)

274 "Spontaneously grabbing your shoes and going out? That's no longer possible." (S12)

275 Technologies: Relief or Overload?

276 Technological aids offer control but can also increase mental load:

277 "Before, I checked 6 to 8 times a day. Now I check constantly." (S10)

278 Some even revert to simpler systems:

279 "I stopped using the closed loop. It was an extra mental burden." (S13)

280 Sport as a Lever for Transformation and Assertion

281 For many runners, sport is not just a health activity—it's a space for self-affirmation, resilience, and identity reconstruction.

283 "I don't do it to prove anything to others, but to prove to myself that it's possible." (S2)

284 Visibility and Advocacy

285 Running becomes a space of visibility and sometimes activism:

286 "It's important to show that the disease doesn't stop us." (S5)

287 Inspiration and Social Role

288 Some runners take on a role model status, especially for young diabetics:

289 "Parents told me it reassured them to see that it's possible." (S6)
290 Self-Management Skills and Learning

291 Ultra-endurance requires deep knowledge of one's body and diabetes. Strategies are highly

292 personalized and often learned through trial and error:

293 "It took me four years to find balance." (S1)

294 Reversing the Meaning of Illness

295 For several runners, the disease paradoxically becomes a source of strength:

296 "My diabetes helped me strengthen my mental resilience." (S1)

297
298 **Discussion**

299 *Contextualizing the results*

300 This study highlights the complexity of living with type 1 diabetes (T1D) in the context of
301 ultra-endurance sports. The diagnosis was frequently described as a biographical rupture,
302 echoing Bury's concept of *biographical disruption* (14), where illness interrupts the
303 continuity of identity and life trajectory. Participants' narratives also resonate with Claire
304 Marin's reflections on illness as an existential fracture that forces a redefinition of self and
305 relationships (15).

306 Beyond the initial shock, the process of acceptance emerged as dynamic and multifaceted. It
307 involved not only medical adaptation but also identity negotiation, emotional regulation, and
308 social positioning. This aligns with Havi Carel's phenomenological perspective, which
309 frames illness as a transformation of bodily experience and a potential source of reflective
310 awareness (16)

311 The findings support previous research suggesting that acceptance of chronic illness is
312 associated with improved emotional and social well-being (17), and with a sense of harmony
313 with oneself (18). In this study, acceptance was often facilitated by sport, peer support, and
314 self-management strategies, reflecting a broader psychosocial adaptation process (19).

315 **The ambivalence expressed by participants regarding their status as "ill" or "sick" illustrates**
316 **the tension between medical categorization and personal identity. Participants' ambivalence**
317 **about being "ill" or "sick" shows the tension between medical labels and personal identity.**
318 **This perspective resonates with recent work on narrative imagination and disability, which**
319 **highlights the prevalence of 'supercrip' narratives and their implications for inclusion (20).**
320 This echoes the work of Bright and Molnár (7), who showed how individuals with T1D use
321 sport to renegotiate identity and resist stigmatization. The narratives collected here further
demonstrate how ultra-endurance can serve as a space for reclaiming agency, reframing illness, and asserting a positive self-image.

*Specificities of Ultra-Endurance*

Ultra-endurance sports represent a particularly demanding context for individuals living with type 1 diabetes. The physical and psychological challenges inherent to these practices intensify the mental load associated with diabetes management, requiring precise anticipation, continuous adaptation, and deep metabolic knowledge. These observations are consistent with broader research on ultra-endurance athletes, which highlights unique physiological demands and motivational profiles in extreme sports contexts (21). Yet, paradoxically, this extreme context also offers a space of freedom, glycemic stability, and self-valorization.

Participants in this study described how ultra-endurance helped them develop advanced self-management skills, often acquired through trial and error and shared within peer communities. These findings align with Paley and Johnson's review (22), which identifies resilience strategies among ultra-endurance athletes—such as acceptance, emotional regulation, and positive reframing—that closely resemble those used by individuals managing chronic illness.

The narratives collected also illustrate how sport can serve as a medium for identity reconfiguration. Illness, rather than being solely a constraint, becomes a driver of self-transcendence and social visibility. This inversion of stigma is particularly evident in the way participants claim their condition, make it visible, and use it to inspire others. Pereira Vargas et al. (8) have shown that athletes can construct authentic identities by embracing vulnerability, provided they retain control over the narrative.
345 These findings contribute to a growing body of literature that explores the intersection of chronic illness, performance, and identity. These findings add to the growing literature on how chronic illness intersects with performance and identity. They suggest that ultra-endurance is not merely a physical challenge, but a symbolic space where individuals negotiate autonomy, resilience, and recognition.
346
347
348
349

350 While the benefits of ultra-endurance practices are evident in terms of identity reconstruction and self-management, it is important to acknowledge that such extreme engagement may also carry risks. Previous research has highlighted potential issues such as physical overload, disordered eating, and exercise dependence among ultra-endurance athletes (23). Although these aspects were not the focus of the present study, they warrant further investigation in future research.
351
352
353
354
355

356 *Strengths and Limitations*

357 This study provides rich insights into the lived experience of individuals with type 1 diabetes engaged in ultra-endurance sports. Its strength lies in the depth of the qualitative data, the reflexive positioning of the researcher, and the use of constructivist grounded theory to capture complex identity dynamics.
358
359
360

361 However, several limitations must be acknowledged. First, the sample size was small (n = 13) and composed of highly engaged athletes, which limits the generalizability of the findings.
362
363 While qualitative research does not aim for statistical representativeness, the homogeneity of the sample—particularly in terms of athletic commitment and involvement in peer-support initiatives—may have favored the expression of empowering narratives.
364
365

366 However, several limitations must be acknowledged. First, the sample size was small (n = 13) and composed of highly engaged athletes, which limits the generalizability of the findings.
367
368 Although qualitative research does not seek statistical representativeness, the sample's
369 homogeneity—especially in athletic commitment and peer-support involvement—may have
370 amplified empowering narratives. Nevertheless, this size is consistent with qualitative
371 standards and reflects the rarity of the target population: individuals living with type 1
diabetes and engaged in ultra-endurance sports are estimated to be fewer than one hundred in
372 France. The gender imbalance (11 men, 2 women) mirrors the reality of ultra-endurance
373 participation, where women typically represent 15–25% of athletes. While this composition
374 limits transferability to other contexts, it remains coherent with the population studied and
375 allowed for rich, diverse narratives.
376

377 Finally, the dual role of the principal investigator as both a healthcare professional and a
person living with type 1 diabetes may have influenced data collection and interpretation.
378 While this insider position facilitated access and enriched understanding, it also raised
379 potential risks of bias. Reflexive strategies—including maintaining a reflexive journal and
380 engaging in regular debriefing with co-authors—were implemented to mitigate these risks
381 and enhance credibility.
382

383 Second, recruitment through social media and peer networks may have introduced a selection
bias, privileging participants already attuned to discourses of performance, autonomy, and
384 resilience. This may have overshadowed more ambivalent or painful experiences, as
385 documented in chronic illness research (24).
386

387 Third, the absence of comparison with other profiles of individuals living with T1D—such as
non-athletes, those practicing other types of physical activity, or individuals in precarious
388 social or medical situations—limits the scope of the conclusions. A comparative or
389 longitudinal design could help refine the understanding of identity trajectories and adaptation
390 strategies across diverse contexts.
391
Finally, the dual role of the principal investigator as both researcher and participant (living with T1D and practicing ultra-endurance) may have influenced data collection and interpretation. Although reflexive strategies were employed to mitigate this risk, including journaling and team triangulation, this insider position remains a methodological consideration.

## *Practical Implications*

The findings of this study underscore the importance of recognizing the experiential knowledge developed by individuals living with type 1 diabetes, particularly those engaged in ultra-endurance sports. These individuals demonstrate advanced self-management skills, including anticipatory regulation, emotional coping, and personalized adaptation strategies. Such expertise, often acquired outside formal healthcare settings, represents a valuable resource for improving therapeutic adherence and patient empowerment (25,26).

For healthcare professionals, these insights call for a shift from a strictly biomedical model toward a more collaborative and patient-centered approach. This includes acknowledging patients as active partners in care, integrating their lived experience into clinical decision-making, and supporting autonomy through tailored education and dialogue (27).

Patient education programs (PEPs) should incorporate psychosocial dimensions, cultural sensitivity, and experiential learning. Several authors have emphasized the need for tailored therapeutic approaches that reflect patients' lived realities and self-management strategies (28). The WHO recommends strengthening such programs to meet the challenges of chronic disease management, especially in contexts where patients must navigate their condition independently (29).

From a health policy perspective, the study highlights the structuring role of peer communities and physical activity in illness acceptance and identity reconstruction. These
416 levers deserve institutional support through inclusive sports initiatives, urban planning that facilitates movement, and recognition of patient associations as legitimate actors in care 417
governance (30–34). 418

419 Endocrinologists and general practitioners should actively discuss patients' ultra-endurance goals and offer tailored advice on insulin, nutrition, and risk management. Rather than discouraging such projects, clinicians can support safe participation by integrating experiential knowledge into therapeutic planning and fostering shared decision-making. 420 421 422
General practitioners, who often maintain long-term relationships with patients, are ideally positioned to coordinate care, monitor overall health, and facilitate dialogue between specialists and patients pursuing extreme physical challenges. 423 424 425

426 *Future Research Directions*

427 This study sheds light on an underexplored area: the subjective experience of chronic illness in the context of extreme sports. It invites further investigation into the intersections between ultra-endurance, identity, and self-management in type 1 diabetes. 428 429

430 Future research could adopt comparative designs, including individuals with T1D who engage in other forms of physical activity or those who do not practice sport, to better understand the diversity of adaptation trajectories. Studies involving non-athletic or socially vulnerable populations would help balance the empowering narratives observed here and reveal other forms of coping or constraint. 431 432 433 434

435 Longitudinal approaches would also be valuable to explore how illness identity evolves over time, in relation to life events, disease progression, and changing social contexts. Shneider et al.(3) have shown that illness identity is dynamic and closely linked to therapeutic adherence and health outcomes. 436 437 438
439 Finally, further research could examine the role of technological tools, peer communities, and healthcare relationships in shaping the experience of chronic illness. These dimensions, addressed in other components of the broader research project, deserve dedicated exploration to inform more inclusive and participatory models of care.

443
444 **Conclusion**

445 This qualitative study, grounded in constructivist grounded theory and reported in accordance
446 with COREQ guidelines, explored the lived experience of individuals with type 1 diabetes
447 engaged in ultra-endurance sports. Through in-depth interviews and rigorous thematic
448 analysis, the study revealed how illness, initially experienced as a biographical rupture, can
449 become a space for adaptation, identity reconstruction, and resilience.

450 Ultra-endurance practices, while demanding, offer opportunities for self-reappropriation,
451 social visibility, and advocacy. Participants developed advanced self-management strategies
452 and reframed their condition as a source of strength rather than limitation.

453 The methodological approach—combining reflexive positioning, triangulation, and
454 interpretive saturation—ensured analytical depth and credibility. While the findings are not
455 statistically generalizable, they provide transferable insights into the psychosocial dynamics
456 of chronic illness in performance-oriented contexts.

457 These results invite a rethinking of support models for chronic illness, emphasizing
458 experiential knowledge, patient autonomy, and the role of peer communities. They also
459 highlight the need for inclusive healthcare approaches that recognize diverse trajectories and
460 forms of bodily engagement.

461 Ultimately, living with type 1 diabetes in ultra-endurance is not only about coping—it is
462 about transforming the illness into a driver for going further, higher, stronger—differently.

463

464
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<table><caption>Table 1. Characteristics of study participants</caption><thead><tr><th>ID</th><th>Sex</th><th>Age</th><th>Age at diagnosis</th><th>Duration of T1D</th><th>Treatment</th><th>CGM</th><th>HbA1c</th><th>Sports practiced</th><th>Max distance</th></tr></thead><tbody><tr><td>S1</td><td>M</td><td>36</td><td>21</td><td>15</td><td>Pump (Omnipod)</td><td>Dexcom</td><td>7.8</td><td>Ultra-trail, ski, tennis-marathon</td><td>200 km</td></tr><tr><td>S2</td><td>M</td><td>26</td><td>15</td><td>11</td><td>MDI (pens)</td><td>Libre 2</td><td>N/A</td><td>Trail, triathlon, rugby-marathon</td><td>80 km</td></tr><tr><td>S3</td><td>M</td><td>53</td><td>38</td><td>15</td><td>Pump (Omnipod Dash)</td><td>Dexcom</td><td>N/A</td><td>Ultra-trail-marathon</td><td>108 km</td></tr><tr><td>S4</td><td>M</td><td>48</td><td>25</td><td>23</td><td>Pump (Omnipod, Diabeloop planned)</td><td>Dexcom G6</td><td>7.4</td><td>Trail, marathon</td><td>59 km</td></tr><tr><td>S5</td><td>F</td><td>49</td><td>23</td><td>27</td><td>Pump</td><td>Dexcom</td><td>5.8</td><td>Trail, ultra cycling, Marathon, triathlon</td><td>42 km</td></tr><tr><td>S6</td><td>M</td><td>41</td><td>19</td><td>22</td><td>Pump</td><td>Dexcom</td><td>N/A</td><td>Trail-marathon</td><td>50 km</td></tr><tr><td>S7</td><td>M</td><td>66</td><td>40</td><td>26</td><td>MDI (pens)</td><td>Libre</td><td>6.7</td><td>Trail-marathon</td><td>50 km</td></tr><tr><td>S8</td><td>M</td><td>37</td><td>13</td><td>24</td><td>Pump</td><td>Dexcom</td><td>N/A</td><td>Trail-marathon</td><td>60 km</td></tr><tr><td>S9</td><td>M</td><td>46</td><td>42</td><td>4</td><td>MDI (pens)</td><td>Libre</td><td>N/A</td><td>Trail-marathon</td><td>42 km</td></tr><tr><td>S10</td><td>M</td><td>38</td><td>10</td><td>28</td><td>Pump</td><td>Dexcom</td><td>6.4-6.5</td><td>Trail-marathon</td><td>100 km</td></tr><tr><td>S11</td><td>M</td><td>44</td><td>19</td><td>25</td><td>Pump</td><td>Dexcom</td><td>6-6.2</td><td>Trail-marathon</td><td>80 km</td></tr><tr><td>S12</td><td>M</td><td>26</td><td>23</td><td>3</td><td>MDI (pens)</td><td>Libre</td><td>N/A</td><td>Trail-marathon</td><td>42 km</td></tr><tr><td>S13</td><td>F</td><td>46</td><td>16</td><td>30</td><td>Pump</td><td>Dexcom</td><td>N/A</td><td>Trail-marathon</td><td>50 km</td></tr></tbody></table>

This table summarizes demographic and clinical characteristics of participants, including age, diabetes duration, treatment type, technology use, and athletic background. HbA1c values were not systematically collected; they are reported only when spontaneously mentioned by
582 participants during interviews, in accordance with the protocol approved by the ethics
583 committee.

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**Response to Reviewers**

Dear Reviewers,

I would like to sincerely thank both reviewers for the time and effort devoted to reviewing my manuscript, which explores the lived experience of chronic illness—specifically type 1 diabetes—in the context of ultra-endurance sports. Your comments and suggestions have been extremely valuable and have significantly improved the quality of this work.

**Revisions Implemented**

* **Title:** The title has been revised to make it more precise and aligned with PLOS ONE style guidelines.

* **Participant Table:** The table has been enriched with additional data from interviews (age, sex, diabetes duration, technology use, type of race), while respecting ethical constraints. Race names were omitted to preserve anonymity.

* **Ethics and Data Access:** The ethics approval statement now appears only in the Methods section. The institutional contact for data access has been corrected (Data Access Committee, Université de Lorraine).

* **References:** The reference list was checked for retracted articles. Two suggested references could not be retrieved despite extensive searches. However, the concept of *supercrip narratives* was incorporated through the publication by Williams et al. (2021).

* **Sample Justification:** The sample size (n = 13) is consistent with qualitative research standards and reflects the rarity of the target population (likely fewer than one hundred ultra-endurance athletes with type 1 diabetes in France). The gender distribution (15% women) mirrors the reality of ultra-endurance events, where female participation remains limited but is gradually increasing.

* **Reflexivity:** I expanded the description of my dual role as both a physician and a person living with type 1 diabetes, and detailed strategies to minimize bias (reflexive journaling, triangulation with co-authors). This is addressed in the Methods section and acknowledged in the limitations.

* **Clinical Implications:** A paragraph was added to highlight how endocrinologists and primary care physicians can support patients pursuing ultra-endurance goals through individualized guidance and collaborative care.

* **Language and Style:** Several sentences were revised to improve clarity and readability, following your recommendation for a more fluent style.

To facilitate your review, a detailed **point-by-point response table** is provided below.

Once again, thank you for your constructive feedback. I hope this revised version meets your expectations and reflects the quality standards of PLOS ONE.

Best regards

The first author on behalf of the team
<table><caption>Point-by-Point Response Table :</caption><thead><tr><td>Reviewer Comment</td><td>Response</td></tr></thead><tbody><tr><td>Title: Please revise the manuscript title to remove redundant wording.</td><td>The title was revised to “Chronic Illness and Extreme Performance: Type 1 Diabetes in Ultra-Endurance” to improve clarity and comply with PLOS ONE style.</td></tr><tr><td>Participant Table: Add pseudonymized data and relevant characteristics.</td><td>The table was expanded to include age, sex, diabetes duration, technology use, and type of race, while respecting anonymity and ethical constraints.</td></tr><tr><td>Reflexivity: Elaborate on the dual role of the researcher and strategies to limit bias.</td><td>A dedicated paragraph was added in the Methods section detailing the principal investigator's dual role and mitigation strategies (reflexive journaling, triangulation).</td></tr><tr><td>Sample Composition: Discuss size and gender bias.</td><td>Added justification in Strengths and Limitations: sample size aligns with qualitative standards and reflects the rarity of the population; gender distribution mirrors ultra-endurance participation trends.</td></tr><tr><td>Clinical Implications: How can endocrinologists support these</td><td>A paragraph was added in Practical Implications, highlighting the role of endocrinologists and general practitioners in supporting safe participation through individualized guidance and collaborative care.</td></tr><tr><td>References: Include suggested citations.</td><td>Integrated Williams et al. (2021) for supercrip narratives. Other suggested references could not be retrieved despite extensive searches.</td></tr><tr><td>Language and Style: Improve</td><td>Several sentences were revised for clarity and readability throughout the manuscript.</td></tr></tbody></table>