Table 1.
Subject characterization | Winter swimmers (n = 7) | Control group (n = 8) | p |
---|---|---|---|
Age (years) | 25 (2.5) | 23.6 (2.0) | 0.25 |
Weight (kg) | 76.7 | 78.9 | 0.55 |
Physical training/week (h) | 7 | 6 | 0.32 |
Vegetarian (n) | 1 | 1 | – |
BMI (kg/m2) | 23.7 (4.8) | 23.3 (1.8) | 0.87 |
VO2max (mL O2/kg/min) | 53.1 (4.8) | 51.2 (6.0) | 0.50 |
Fasting plasma insulin (pmol/L) | 37 (15.5) | 33 (11.4) | 0.60 |
Fasting plasma glucose (mmol/L) | 4.6 (0.3) | 4.5 (0.5) | 0.58 |
Total cholesterol (mmol/L) | 4.3 (0.9) | 4.0 (0.4) | 0.48 |
HDL cholesterol (mmol/L) | 1.5 (0.4) | 1.4 (0.2) | 0.53 |
LDL cholesterol (mmol/L) | 2.7 (0.9) | 2.5 (0.5) | 0.57 |
Tissue fat (%) | 12.0 (4.6) | 18.2 (4.3) | 0.01 |
Gynoid fat (%) | 16.6 (6.1) | 23.3 (5.4) | 0.03 |
Android fat (%) | 16.8 (8.7) | 23.3 (6.9) | 0.12 |
Resting energy expenditure thermal comfort state (kcal/24 h) | 2,038 (96.0) | 2,005 (209.6) | 0.69 |
Resting energy expenditure during 30 min cooling (kcal/24 h) | 3,044 (337.2) | 2,560 (348.1) | 0.01 |
Winter swimming | |||
Winter-swimming seasons in total | 1.8 (0.9) | – | – |
Total swims last month | 10.6 (3.3) | – | – |
Swims/week the last month before experiments | 2.6 (0.1) | – | – |
Number of immersions/visit | 2.6 (0.8) | – | – |
Time in water/immersion (min) | 1.4 (2.6) | – | – |
Sauna users (yes/no) | (7/1) | – | – |
Number of sauna visits/visit | 2 | – | – |
Time in sauna/visit (min) | 11.1 (14.3) | – | – |
Total time immersed in cold water/week (min) | 11 | – | – |
Total time in sauna heat/week (min) | 57 | – | – |
HDL, high-density lipoprotein; LDL, low-density lipoprotein. Data are given as mean with the standard deviation (SD) in brackets. Differences between groups are evaluated using Student’s unpaired t test. See also Table S1.