Clinical trial NCT06346639: Effect of a 16-day Hot and Cold Acclimation on Adaptive Responses and Health-related Indicators
Official title: Time Course of Adaptive Responses in Humans During a 16-day Hot and Cold Acclimation Program, and Its Effect on Health-related Indicators
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Healthy
Lead sponsor: Lithuanian Sports University
Sponsor class: OTHER
First posted: 2024-04-04
Enrollment: 31
Sex: ALL
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: PREVENTION

Brief summary: There are no previous studies of the effects of a combination of whole-body immersions in hot and cold baths on adaptive responses and health-related markers. Thus, the primary aim of this project is to determine whether interventions consisting of whole body immersion in hot and cold baths over 16 days develop heat and/or cold adaptation by remodeling thermoregulatory, metabolic, cardiovascular and physiological responses, and the secondary aim is to determine if current cold-hot acclimation has any effects on physical and mental health-related markers.


Eligibility criteria: Inclusion Criteria:

* young, healthy, non-obese males and females;
* nonsmoker;
* no needle phobia;
* not taking medication and/or dietary supplements that may affect experimental variables.

Exclusion Criteria:

* neurological, cardiovascular, metabolic, and/or inflammatory diseases, or conditions that could be worsened by exposure to acute thermal stimuli and that could affect experimental variables;
* involvement in temperature manipulation program for ≥ 3 months;
* attendance at any excessive formal physical exercise or sports program.

Primary outcomes:
measure: Change in body mass and body composition (kg)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in skinfold thickness (mm)
timeFrame: Before acclimation (1st day), 2 days and 2 weeks after the end of acclimation (44 th and 51st day)
measure: Change in body mass index (kg/m^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in body surface area (m^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in substrate oxidation
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in substrate oxidation (g/day)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in ventilation (l/min)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in breathing frequency (t/min)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in resting energy expenditure (kcal/day)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in metabolic heat production (W)
timeFrame: during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days)
measure: Change in heart rate (bpm)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in blood pressure (mmHg)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in mean arterial pressure (mmHg)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in heart rate variability (ms)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in heart rate variability (time domain) (ms)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in heart rate variability (time domain) (Ln)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in heart rate variability (frequency domain) (ms^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in heart rate variability (frequency domain) (Ln)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in stroke volume (ml)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in stroke volume index (ml/m^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in cardiac output index (l/min//m^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in cardiac output index (l/min)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in contractility index
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in ventricular ejection time (ms)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in ventricular ejection fraction (percent)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in end diastolic volume (ml)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in systemic vascular resistance (dyn.s/cm5.m^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in cardiac work index (kg.m/m^2)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in early diastolic filling ratio (percent)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in testosterone concentration (µg/dl)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in female sex hormones concentration (pg/mL)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in salivary cortisol concentration (µg/dl)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in cytokines concentrations (pg/ml)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in complete blood count (10^9/L)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in complete blood count (percent)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in lipid profile (mmol/l)
timeFrame: Before acclimation (1st day),during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in catecholamines concentration (ng/ml)
timeFrame: Before acclimation (1st day),during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in insulin concentration (μIU/ml)
timeFrame: Before acclimation (1st day), 2nd day and 2 weeks after the end of acclimation (44th and 51st days)
measure: Change in glucose tolerance (mmol/l)
timeFrame: Before acclimation (1st day), 2nd day and 2 weeks after the end of acclimation (44th and 51st days)
measure: Change in anxiety and depression (points)
timeFrame: Before acclimation (1st day), 2nd day and 2 weeks after the end of acclimation (44th and 51st days)
measure: Change in plasma metabolites of the kynurenine pathway (μm)
timeFrame: Before acclimation (1st day), during baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in body temperature (°C)
timeFrame: During baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days), and 2 weeks after the end of acclimation (51st day)
measure: Change in physiological strain index
timeFrame: During baseline provocative heat test (8th or 15th day), during acclimation (from 22 to 37th days), during repeated provocative heat test (41st or 42nd days)
measure: Change in cold strain index
timeFrame: During baseline provocative cold test (8th or 15th day), during acclimation (from 22 to 37th days), during repeated provocative cold test (41st or 42nd days)
measure: Change in root mean square (RMS) amplitude (mV)
timeFrame: During baseline provocative cold test (8th or 15th day), during acclimation (from 22 to 37th days), during repeated provocative cold test (41st or 42nd day)
measure: Change in pain sensations
timeFrame: During baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st or 42nd day)
measure: Change in thermal sensations (points)
timeFrame: During baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st or 42nd day)
measure: Change in shivering/sweating (points)
timeFrame: During baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st or 42nd day)
measure: Change in thermal comfort (points)
timeFrame: During baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st or 42nd day)
Secondary outcomes:
measure: Height (m)
timeFrame: Before acclimation (1st day)
measure: Change in physical activity (in h)
timeFrame: 3 days before first assessment, during 16-day acclimation period and during 2 week post-acclimation period.
measure: Change in sleep (in h)
timeFrame: 3 days before first assessment, during 16-day acclimation period and during 2 week post-acclimation period.
measure: Change in oxygen saturation (percent)
timeFrame: During baseline provocative tests (8th and 15th day), during acclimation (from 22 to 37th days), during repeated provocative tests (41st and 42nd days)
Other outcomes:
Locations:
city: Kaunas
country: Lithuania
facility: Lithuanian Sports University
Study officials:
affiliation: Lithuanian Sports University
name: Laura Jarutienė
role: PRINCIPAL_INVESTIGATOR
References: