[Endurance bicycle ergometry at 0 degrees C: cardio-respiratory and metabolic course]

The purpose of the present study is to determine the physiological and metabolic variations during and after an exhaustive exercise in different thermal conditions (0 degree C and 20 degrees C). For the eleven experimental subjects, the maximal power output is the same at 0 degrees C and 20 degrees C: 330 +/- 30 W (Mean +/- s). The heart rate is lower (bradycardia) at rest, exhaustion, and recovery. However, these differences are only significant (p less than 0.05) at exhaustion. The oxygen consumption and pulmonary ventilation is higher at 0 degree C in comparison with the measurements at 20 degrees C. The blood lactate concentrations are significantly lower at 0 degree C and we observe the inverse phenomenon for the bicarbonates. The bases excess was significant at 4, 6 and 10th minute of recovery time. These values are higher for the measurements taken at 0 degree C. The results have shown that the cold stress after an exhaustive exercise and during recovery, can induce a physiological and metabolic response unlike of those at 20 degrees C.