Thermoregulatory Influence of a Cooling Vest on Hyperthermic Athletes

Abstract Context: Athletic trainers must have sound evidence for the best practices in treating and preventing heat-related emergencies and potentially catastrophic events. Objective: To examine the effectiveness of a superficial cooling vest on core body temperature (Tc) and skin temperature (Tsk) in hypohydrated hyperthermic male participants. Design: A randomized control design with 2 experimental groups. Setting: Participants exercised by completing the heat-stress trial in a hot, humid environment (ambient temperature  =  33.1 ± 3.1°C, relative humidity  =  55.1 ± 8.9%, wind speed  =  2.1 ± 1.1 km/hr) until a Tc of 38.7 ± 0.3°C and a body mass loss of 3.27 ± 0.1% were achieved. Patients or Other Participants: Ten healthy males (age  =  25.6 ± 1.6 years, mass  =  80.3 ± 13.7 kg). Intervention(s): Recovery in a thermoneutral environment wearing a cooling vest or without wearing a cooling vest until Tc returned to baseline. Main Outcome Measure(s): Rectal Tc, arm Tsk, time to return to baseline Tc, and cooling rate. Results: During the heat-stress trial, Tc significantly increased (3.6%) and, at 30 minutes of recovery, Tc had decreased significantly (2.6%) for both groups. Although not significant, the time for return to baseline Tc was 22.6% faster for the vest group (43.8 ± 15.1 minutes) than for the no-vest group (56.6 ± 18.0 minutes), and the cooling rate for the vest group (0.0298 ± 0.0072°C/min) was not significantly different from the cooling rate for the no-vest group (0.0280 ± 0.0074°C/min). The Tsk during recovery was significantly higher (2.1%) in the vest group than in the no-vest group and was significantly lower (7.1%) at 30 minutes than at 0 minutes for both groups. Conclusions: We do not recommend using the cooling vest to rapidly reduce elevated Tc. Ice-water immersion should remain the standard of care for rapidly cooling severely hyperthermic individuals.