Effect of a 5 min cold water immersion recovery on exercise performance in the heat

Abstract

This study examined the effect of a 5-min cold water immersion (CWI; 14°C) recovery intervention on repeated cycling performance in the heat. Ten male cyclists performed two bouts of a 25-min constant paced (254±22W) cycling session (CP) followed by a 4-km time trial (TT) in hot conditions (35°C, 40% relative humidity). The two bouts were separated by either 15-min of seated recovery in the heat (CON), or the same condition with 5-min CWI (5th-10th min), in a counterbalanced cross-over design (CP1TT1 → CWI or CON → CP2TT2). Rectal temperature (T^re) was measured immediately before and after both the CP sessions and 4 km TTs. Cycling economy and VO₂ were measured during the CP sessions and the average power output (PO) and completion times (CT) were recorded for each TT. Compared with CON, T^re was significantly lower (0.5±0.4°C) in CWI before CP2 until the end of TT2. However, the increase in T^re (0.5±0.2°C) during CP2 was not significantly different between conditions. During TT2, PO was significantly greater in CWI (327.9 ± 55.7 W) compared with CON (288.0 ± 58.8 W), leading to a faster CT in CWI (6.1 ± 0.3 s) compared with CON (6.4 ± 0.5 s). Economy and VO₂ were not influence by the CWI recovery intervention. In conclusion, 5-min CWI recovery significantly lowered T^re and maintained endurance performance during subsequent high-intensity exercise. These data indicate that repeated exercise performance in heat may be improved when a short period of CWI is applied during the recovery period.