Resumen de Efficacy of Field Treatments to Reduce Body Core Temperature in Hyperthermic Subjects
Wade H. Sinclair, Stephan Rudzki, Anthony S. Leicht, Alison L. Fogarty, Susan K. Winter
Purpose: To contrast the effects of three postcooling techniques in reducing body core temperature (Tc) in exercise-induced hyperthermic participants on the cessation of exercise.
Methods: Eleven healthy active male volunteers were cooled during a 40-min period using three different methods: ice packs to the neck, axillae, and groin (ICE); water spray and fan (FAN); and 2 L of chilled (20[degrees]C) intravenous saline administered during a 20-min period (IV). Rate of decrease in Tc, cardiovascular responses, and any incidence of reported adverse effects were investigated. Trials were presented in a counterbalanced order with the volunteers' body core temperature being elevated to 40.0[degrees]C on three occasions via an intermittent walk-run (2 min at 6 km[middle dot]h-1 and 4 min at 10 km[middle dot]h-1) protocol conducted within a climate-controlled chamber (34.2 +/- 0.5[degrees]C and 62.3 +/- 3.1% relative humidity).
Results: Rate of Tc reduction during the first 20 min of ooling was greater for FAN compared with ICE (0.09 +/- 0.02[degrees]C[middle dot]min-1 vs 0.07 +/- 0.02[degrees]C[middle dot]min-1, P < 0.05), whereas IV did not differ with the other trials (0.08 +/- 0.01[degrees]C[middle dot]min-1, P > 0.05). Three participants complained of numbness or paresthesia in their arm or hand during administration of the chilled saline, although these symptoms resolved within 5 min of ceasing the infusion.
Conclusions: All three cooling techniques reduced Tc and would be suitable for first aid application in a field setting during transportation to adequate medical facilities. Chilled IV saline did not produce any contraindications, providing a suitable alternative for Tc cooling
