The idea that athletic performance in hot weather can be improved by cooling relatively small portions of the body is an attractive one. Nevertheless, trying to compete in an endurance race in soaring temperatures with a bag of frozen peas strapped to your head may not prove a practical solution.

Recently, researchers in New York and Kentucky investigated the effectiveness of a commercially available head-neck cooling device during endurance cycling (D.G. Burke, T.W. Pelham & L.E. Holt, 'Effectiveness of a commercial head-neck cooling device,' The Journal of Strength and Conditioning Research, Vol. 13, No. 3, August 1999). They set out to see if the 'Kool-It' device, which consists of a polyfoam core capable of absorbing 10 times its weight in water, could provide actual relief from the effects of heat stress.

Twenty subjects (10 male and 10 female) took part in two trials. Both groups cycled for 30 minutes at 60% VO2max in temperatures of 30 ± 1.0 deg C and relative humidity 25 ± 5%. In one of the trials the subjects wore the 'Kool-It' device.

Metabolic and cardiovascular responses were monitored throughout the test procedures. Results indicated that the 'Kool-It' device offered no significant relief from heat stress during the 30-minute ride or during recovery. Both rectal and oesophageal temperatures remained the same. Although 'Kool-It' caused a significant reduction in head skin temperature during exercise and recovery, chest skin temperature was lower only during the first 15 minutes of exercise. More importantly, no significant differences in core temperature were measured, and no significant differences were seen in heart rate, blood pressure, perceived exertion, sweat rate or plasma volume. These findings support earlier research which disputed the potential usefulness and effectiveness of neck-cooling devices and the present researchers concluded that it was unlikely that 'Kool-It' offers any beneficial reductions in core temperature during exercise.