'Clutching a bottle of cold water while exercising can help make you fitter'
07:26 GMT, 14 March 2012
David Cameron, pictured jogging in St James Park, could benefit from holding cool packs in his hands
Do you struggle to jog on the treadmill for more than a few minutes before you're exhausted The solution is surprisingly close at hand.
For as strange as it seems, U.S researchers have found cooling the palms increases your capacity for exercise.
The team from Stanford University, California, said holding something cool, like a bottle of water, means less heat is stored in the body, making it easier to work out for longer.
They studied the effect in a group of obese women aged 30 to 45 following an exercise programme.
All were asked to work 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 routines including push-ups, lunges and using a treadmill.
The goal was to increase exercise duration to 45-minute long sessions at 80 per cent of maximum heart rate.
Keeping cool in the gym makes it easier to train
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, lost almost 3in 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 and were more likely to drop out of the study.
Lead researcher Dr Stacy Sims, said: 'Obese women often complain about sweating and getting tired because they're walking around with extra insulation.
'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.'
The device used in the study is costly and typically found in professional sports training centres and clinics rather than gyms.
But Dr Sims suggested that simply holding a bottle of water could cool the palms and have a similar effect.
The research was presented at an American Heart Association meeting in San Diego, California.