Core Temperature Afterdrop in Cold-water Swimming

Study Overview
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Brief Summary
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A significant risk associated with hypothermia during exercise in a cold environment is the core temperature (T°core) afterdrop, which corresponds to a continuous fall in T°core during rewarming after hypothermia. However, the rate and predictors of the afterdrop are unclear, particularly during prolonged cold water swimming. The investigators propose to measure the changes in T°core during and after a cold water swim at 12.5-13°C qualifying for English Channel swim and to test the impact of anthropometric and swimming parameters on the duration of the T°core afterdrop. The hypotheses are that afterdrop is common during a prolonged cold water swimming event and that protective factors against T°core drop during cold water swimming (increased body fat and BMI) might, conversely, be associated with prolonged afterdrop.

Official Title
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Analysis of Core Temperature Afterdrop and Factors Associated With Afterdrop in Cold-water Swimming

Conditions
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Hypothermia, Accidental, Cold Water Swimming

Intervention / Treatment
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* Other: Swimming participants in the 6-hour cold water swim


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: swimmers taking part in the Channel Swim Camp swimmers above 18 years of age swimmers willing and able to give informed consent for participation in the study Exclusion Criteria: swallowing disorder chronic gastrointestinal disease MRI scheduled within 48 hours after the race.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cold water swimmers<br>swimmers participating in the 6-hour cold water swim, qualifying for the English Channel Swim | Other: Swimming participants in the 6-hour cold water swim<br>* The 6-hour cold water swim was the qualifying swim for the English Channel swim during the Channel Swim Camp Dinard 2021 and participants were the swimmers registered for the 6-hour cold water swim who volunteered to participate in this study<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Body Core Temperature | Measurement of Body Core Temperature using an ingestible electronic sensor (e-Celsius®, BodyCap , Caen, France) which provide a continuous validated measurement | Continuous measurement was collected from 30 minutes before the race until 2 hours after the end of the race for each swimmer | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body composition, body mass | Fat mass (in kg, % of body mass [fat mass and body mass were combined to report % of body mass) was measured using bioelectrical impedance analysis (mBCA 525, Seca, Germany). | One measurement assessed the day before the race | 
| Body composition, fat-free mass | Fat-free mass (in kg, % of body mass [fat-free mass and body mass were combined to report % of body mass) was measured using bioelectrical impedance analysis (mBCA 525, Seca, Germany). | One measurement assessed the day before the race | 
| Body composition, muscle mass | Muscle mass (in kg, % of body mass [muscle mass and body mass were combined to report % of body mass) was measured using bioelectrical impedance analysis (mBCA 525, Seca, Germany). | One measurement assessed the day before the race | 
| Distance | Distance of the swimming | The distance of swimming was collected from the organisers immediately after the race | 
| Duration | Duration of the swimming | The duration of swimming was collected from the organisers immediately after the race | 
| Individual characteristics, gender | The variable collected was the gender of participants | One evaluation assessed the day before the race | 
| Individual characteristics, age | The variables collected was the age of participants | One evaluation assessed the day before the race | 
| Individual characteristics, swimming habits | The variables collected was the swimming distance per week (total, swimming pool and open water) | One evaluation assessed the day before the race | 
| Individual characteristics, training in cold environment | The variable collected was the type of specific training in cold environment (yes/no) | One evaluation assessed the day before the race |