A study presented at the American Heart Association’s Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2012 scientific sessions showed cooling the palms of obese women’s hands while they exercised meant they could exercise longer. ‘The palmar surfaces of the hands and feet are the key radiator heaters of the body,’ says Stacy Sims, who is the study’s lead researcher and an exercise physiologist and nutrition scientist at Stanford University. ‘By cooling blood through the palms, you’re able to cool more blood returning to the heart.’
In the study, 24 obese women aged 30 to 45 were randomly assigned to either a cooling or control group. The women attended three exercise sessions a week for the study’s three-month period, including 10 minutes of body-weight exercises, 25 to 45 minutes of treadmill walking and 10 minutes of core-strengthening exercises. All the women exercised while holding a metal cylinder that circulates water. Women in the cooling group used the device with a circulating temperature of 16°C, while the control group’s device remained at body temperature (37°C).
At the end of the three-month period, women in the cooling group were more likely to complete the full 45-minute treadmill walk. They had shaved an ‘average of five minutes off the time it took to walk 1.5 miles, dropped nearly three inches off their waists, and had lower resting blood pressure and a greater exercise heart rate. Women in the control group saw no significant changes.
Overweight women may feel particularly uncomfortable when exercising because the insulating effects of body fat can lead to overheating, fatigue, exhaustion and rapid heart rate. ‘It would feel like Lance Armstrong doing the Tour de France in a wetsuit,’ says Sims.
The study was designed to improve cardiovascular and muscular fitness so women would feel more fit and have the confidence to join fitness programs. Helping overweight or obese women avoid overheating during a workout ‘makes them more comfortable, which is a positive reinforcement to exercise.’
Since the cooling device used in the study is costly and not yet widely available, Sims suggests holding a cold water bottle while exercising. She also notes hydration is important and suggests taking sips of cold water while working out.
Sims cautions against placing ice anywhere on the body, explaining that this would cause your blood vessels to constrict, sending blood back into circulation before it’s had a chance to cool.