AIRFLOW NEEDED TO CONTROL THERMOREGULATION IN THE HEAT

Mora-Rodriguez, R., Del Coso, J., Aguado-Jiminez, R., & Estevez, E. (2007). Separate and combined effects of airflow and rehydration during exercise in the heat. Medicine and Science in Sports and Exercise, 39, 1720-1726.

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This study evaluated if airflow is required to obtain the beneficial effects of rehydration (thermoregulatory and cardiovascular) during exercise in dry heat. Moderately trained heat-acclimated males (N = 10) pedaled for 60 minutes at 60% VO2max in a hot-dry (36C) environment on four different occasions: 1) without rehydration or forced airflow (control trial); 2) rehydrating 100% of sweat losses by ingesting a 6% carbohydrate-electrolyte solution; 3) receiving airflow at a velocity of 2.55 m/second; and 4) combining airflow and rehydration.

Without airflow, rehydration alone did not lower rectal temperature below the control value. With airflow, rehydration reduced final rectal temperature. In the trials with wind, skin temperature was reduced ~0.6C, and heart rate drift was prevented. In trials with rehydration, cardiac output was maintained higher than in the control condition.

Implication. When exercising in a hot-dry environment, airflow is required for rehydration to improve thermoregulation and cardiovascular function.

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