Research has shown cooling the palms of the hands increases capacity for exercise. Less heat is stored in the body, making it easier to work out for longer.
Scientists in the US studied the effect in a group of obese women aged 30 to 45 following an exercise routine. All worked out with their hands in a palm-cooling device containing water at different temperatures.
For half the 24 women, the water was at 16C, while for the other half the temperature was raised to the normal body level of 37C. Participants went through the same fitness programme involving push-ups, lunges and using a treadmill.
Over a period of three months the women with cooled hands shaved an average five minutes off the time taken to walk 1.5 miles (2.4km), lost almost 3in (7.6cm) off their waists, lowered their resting blood pressure and increased their exercise heart rate. Those whose hands were kept at body temperature showed no such improvement.
Lead researcher Dr Stacy Sims, from Stanford University in California, said: “If you can slow the rate internal temperature rises and cool someone who is obese, they don’t store as much heat and don’t feel as uncomfortable. They can do more work.”