Thermoregulatory influence of a cooling vest on hyperthermic athletes.

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 (T(c)) and skin temperature (T(sk)) 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 degrees C, relative humidity = 55.1 +/- 8.9%, wind speed = 2.1 +/- 1.1 km/hr) until a T(c) of 38.7 +/- 0.3 degrees 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 T(c) returned to baseline.

MAIN OUTCOME MEASURE(S): Rectal T(c), arm T(sk), time to return to baseline T(c), and cooling rate.

RESULTS: During the heat-stress trial, T(c) significantly increased (3.6%) and, at 30 minutes of recovery, T(c) had decreased significantly (2.6%) for both groups. Although not significant, the time for return to baseline T(c) 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 degrees C/min) was not significantly different from the cooling rate for the no-vest group (0.0280 +/- 0.0074 degrees C/min). The T(sk) 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 T(c). Ice-water immersion should remain the standard of care for rapidly cooling severely hyperthermic individuals.