Effects of 7°C environmental temperature during a 3-week training period

Approximately three weeks is required for cold temperature acclimation to occur. However, the effects of cold temperature acclimation on fitness and performance remain unknown. Purpose: To determine the impact of cold environmental temperature on training adaptations, fitness measurements, and aerobic performance. Methods: Two groups of twelve inactive male subjects completed 1-hour of cycling in fourteen temperature acclimation trials of either a cold (7°C) or room temperature (20°C) environmental temperature. A performance trial and tolerance trial occurred pre- and post-acclimation. The performance trials assessed VO2peak and body composition. Skin and core temperature were recorded during the 1-hour tolerance trials. Tympanic temperature, heart rate, and power output were recorded during the acclimation trials. Results: No difference occurred in tympanic temperature or heart rate from start to end of the acclimation trials or between temperatures (p\u3e0.05). Power increased during the acclimation (p\u3c0.001) but was not different between temperatures (p=0.169). VO2peak increased and percent body fat decreased from pre-acclimation to post-acclimation performance trials (p\u3c0.001) but neither were different between temperature groups (p\u3e0.05). Core and skin temperature did not change between the tolerance trials or between temperature groups (p\u3e0.05). Heart rate decreased (p\u3c0.001) and sweat rate increased (p=0.050) between the tolerance trials but were not different between temperatures (p\u3e0.05). Conclusion: These data indicate that a three-week acclimation period increases markers of fitness and aerobic performance, but no difference occurs between temperatures. Training period length and fitness status of the subjects may impact results and should be further investigated in cold environmental temperatures