A significant medical risk associated with hypothermia during exercise in a cold environment cardiac arrhythmia due to a possible autonomic conflict. However, little is known about the changes in heart rate and cardiac function after prolonged cold water swimming. The investigators propose to measure the changes in core temperarure during and after a cold water swim at at a water temperature below 15.5°C qualifying for English Channel swim and to test the association with changes in heart rate variability, resting electrocardiogram and left ventricle function.
Study Type
OBSERVATIONAL
Enrollment
20
CHU Caen Normandie
Caen, France
Heart rate from a resting ECG recording
Waves, intervals \& segments of the normal ECG trace was collected
Time frame: Two Time points (1) the day before the race and (2) at 30 min after ending the race
Heart rate from a 5-minute ECG recording
Heart rate variability (HRV) parameters including time-domain measures and frequency-time measures
Time frame: Two Time points (1) the day before the race and (2) at 30 min after ending the race
Transthoracic echocardiography (TTE) analysis
Left and right ventricular and atrial dimensions, and systolic and diastolic ventricular function assessment were collected
Time frame: Two Time points (1) the day before the race and (2) at 30 min after ending the race
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
Time frame: Time Frame: Continuous measurement was collected from 30 minutes before the race until 2 hours after the end of the race for each swimmer]
Body composition, body fat 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).
Time frame: 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).
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Time frame: One measurement assessed the day before the race
Duration
Duration of the swimming
Time frame: The duration of swimming was collected from the organisers immediately after the race
Individual characteristics, gender
The variable collected was the gender of participants
Time frame: One evaluation assessed the day before the race
Individual characteristics, age
The variable collected was the age of participants
Time frame: 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)
Time frame: One evaluation assessed the day before the race