CONVECTIVE COOLING IS BETTER TAN PRE-COOLING IN ENDURANCE EXERCISE

Morrison, S. A., Cotter, J. D., & Cheung, S. S. (2006). Are the benefits of pre-cooling overestimated? Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 827.

This study determined the metabolic, work, and body heat storage effects of pre-cooling and airflow (forced evaporative/convective cooling) on cycling performance in a hot environment. Healthy men (N = 10) completed four experimental trials in balanced order: 1) no pre-cooling before exercise, no wind during exercise (control); 2) no pre-cooling, wind velocity ~4.8 m/s during exercise; 3) pre-cooling, no wind; and 4) pre-cooling plus wind. Pre-cooling was via chest-deep water immersion (~24°C) for either one hour or until core temperature decreased by 0.5°C. Participants then cycled at 95% ventilatory threshold in a hot environment (30°C, 50% RH) until either volitional exhaustion, core temperature exceeded 39.5°C, or 95% maximum heart rate.

Endurance time was extended by 30 + 23 minutes with airflow and 16 +15 min with pre-cooling relative to the control condition. There was no added advantage by combining the two cooling procedures. Wind alone had a greater effect on heat removal than pre-cooling.

Implication. Pre-cooling can be an effective means of increasing overall work, although similar or better benefits can be achieved by providing adequate convective cooling during laboratory exercise in the heat.

Return to Table of Contents for this issue.