Exercise Secret: Do Cool Palms Boost Tolerance?
Could cool hands be the ticket to finally sticking with your workout routine?
According to a small, new study, it could indeed.
The findings, being presented at an American Heart Association meeting Tuesday, suggest that obese women who work out while holding a device that cooled their hands improved their overall cardiovascular fitness, as well as their exercise tolerance. The act of cooling the palms may help combat common obstacles to exercise, such as overheating, sweating, fatigue and rapid heart rate.
"The palmar surfaces in the hands and feet are the biggest heat controllers in the body" said Stacy Sims, an exercise physiologist and nutrition scientist at Stanford University, and lead researcher on the study.
"This has been done with elite athletes," she continued. "My thought process was, if it works really well in people that are conditioned, then maybe it will help for sedentary adults."
In the study, researchers recruited 24 healthy women ages 30 to 45 who had body mass indices between 30 and 34.9. (Body mass index is a measurement of weight relative to height. A normal weight is considered between 18.5 to 24.9; overweight is 25 to 29.9 and anyone with a BMI of 30 or greater is considered obese.)
The women were randomly placed into two groups. Both used an AvaCore Rapid Thermal Exchange device -- a glove containing circulating water -- but one group had 61-degree water circulating, while the control group's device contained 98-degree water. The women attended three exercise sessions per week for three months, completing 10 minutes of body weight exercise, up to 45 minutes of walking on the treadmill and 10 minutes of core strengthening exercises.
Overall, women in the cooling group shaved an average of five minutes off the time it took them to walk a mile and a half, shed almost 3 inches from their waists and had lower resting blood pressure. They also had a greater exercise heart rate.
"What we're looking at is this kind of pre-fitness fitness," Sims said. "If you think about a population of 30- to 45-year-old sedentary, obese women who want to get fit, but are in that really uncomfortable stage where 'My heart rate's high, I'm sweating a lot' -- we're reducing these barriers."
Sims said that women in the cooling group had much lower attrition rates than those in the control.
"I think it's an intriguing study, because it's showing that having hand-cooling actually does improve endurance and delays fatigue," said Carol Ewing Garber, director of the graduate program in applied physiology at Columbia University, who was not associated with the research. She said the exact, underlying mechanism is unclear -- it may be that cooling in general helps boost performance, or that there's something specific to cooling the palms that improves blood flow to the working muscles and also impacts the motor neurons that cool the muscle.
The new study does have limitations in terms of general application.
The device used in the trial is expensive, Sims said, and not widely available.
Garber said that until the impact of holding an ice pack or a cold water bottle is studied, people should "stand by," although Sims said that people with exercise problems may want to try holding an icy water bottle while also making sure to drink plenty of water to help bring their temperatures down.
For now, she is excited about the potential public health benefits this study suggests -- providing a simple boost for the more than one-third of adults in the U.S. who are currently obese.
"There are a lot of psychological barriers that people don't know how to overcome," Sims told The Huffington Post. "If we can allow them to do that in a relatively personal setting and give them options to decrease their heat, we're helping to take them from that state of sitting on the couch to working out in the gym."