Effect of a practical neck cooling device on core temperature during exercise.

Previous studies have documented the effectiveness of combined head and neck cooling in reducing thermal stress during exercise. However, these studies investigated low intensity exercise and devices that are not practical for use on a widespread basis during recreational exercise. In the present study, we investigated the effect of a commercially available, practical neck cooling device on core temperature during strenuous exercise. In a randomized cross-over fashion, 10 male endurance athletes (age 29 +/- 2 yr) performed a 45-min submaximal run (Borg rating of perceived exertion approximately 15) at a constant speed, with and without neck cooling. Runs were conducted on an indoor track, where the ambient temperature was maintained at approximately 21 degrees C dry bulb and approximately 17 degrees C wet bulb. Exercise heart rates and subjective perception of effort were not significantly modified by neck cooling. In contrast, rectal temperature rises (by 0.21 degrees C or 9.5%, P less than 0.02) and sweat rates (by 92 ml.h-1 or 6.4%, P less than 0.02) were reduced by neck cooling. Our study therefore concludes that this practical neck cooling device is capable of inducing reductions in thermal stress during strenuous exercise that, although numerically small, are in a direction of potential benefit.