Adding a cooling vest during cycling improves performance in warm and humid conditions

摘要

It is known that warm and humid environment reduces human physical performance. The present study examined whether the use of an ice-vest in such conditions can improve cycling performance. Seven participants cycled with consecutive, non-stop, 10-minute cycles of nine minutes at 60% of their (V) over dot O-2 max punctuated by a one-minute sprint at 80% (V) over dot O-2 max. The cycling protocol was continuously repeated until exhaustion. The protocol was performed with the ice-vest (ICE), worn after 30 min of cycling, and without the ice-vest throughout the protocol (CON). Ventilatory and thermal responses were continuously recorded. Electromyographic (EMG) signals from four muscles of the dominant leg were recorded over one minute, and subjective sensations were evaluated at 10-minute intervals. At exhaustion, the exercise time was recorded. Exercise time improved significantly while wearing the ice-vest from 61 min and 29 s to 74 min and 14 s (+21.5% +/- 7.6: p <0.05). Mean power frequency and amplitude of the EMG revealed decreased neuromuscular fatigue during ICE compared to CON. Ventilatory responses indicated a tendency towards lower ventilation, respiratory quotient was significantly lower and both thermal parameters and subjective sensations indicated lower thermal strain during ICE in comparison to CON. These results suggest that wearing an ice-vest during cycling in warm and humid conditions decreases thermal and physical strain, thereby improving cycling performance. (C) 2011 Elsevier Ltd. All rights reserved.