INSUBCONTINENT EXCLUSIVE:
Women need more cooling than men, despite similar overall changes in body temperature,When body heats up during exercise, it copes in
There are involuntary systems, such as sweating that help it cool off, and voluntary measures, such as dousing with cold water or wearing
(and switching) hats filled with ice, as American Galen Rupp did every five kilometers during Rio 2016 Olympic marathon
(He won a bronze medal.) Voluntary actions are known as "thermal behavior."When it comes to men and women, it appears that not all thermal
behavior is same, during exercise or after, in cooling down
Women seem to need more cooling than men, according to a study, which is "first to highlight sex differences in thermal behavior," said
author Nicole Vargas, a postdoctoral fellow in exercise and nutrition sciences at University at Buffalo's school of public health.The study
was small, but its findings could have an impact on ways to prevent heat injuries, inspire improved designs in sports clothing and
commercial cooling products, and in other areas
Information about thermal behavior also could help athletes deal with heat waves, common due to climate change.When body heats up during
exercise, it copes in several ways.Photo Credit: iStock"The manner in which men and women tolerate and respond to these perceived changes
may have implications not just for apparel manufacturing, but potentially for improving athletic performance, particularly in endurance and
heat-related activities," said Michael Jonesco, a sports medicine specialist at Ohio State University's Wexner Medical Center
He was not involved in study.Vargas and her colleagues believe study also could prove clinically useful in caring for elderly and those
suffering from certain diseases such as multiple sclerosis."We know that elderly and individuals with MS have altered thermoregulatory
patterns, which consist of both a reduced ability to sweat, thereby trapping more heat in their body, and attenuated perceptual cues
pertaining to thermal stimuli, so they may not sense need to cool themselves when necessary," Vargas said
Thus, it's important to study thermal behavior in these groups to determine whether it could help with their symptoms, "or at least improve
their levels of thermal comfort," she said.In study, scientists had 10 men and 10 women in their early 20s exercise at low intensity - about
65 revolutions per minute - on a stationary bicycle for one hour while watching a nature documentary
Each subject had access to a custom-made dual tubing system that was in direct contact with back of their neck.One set of tubing contained
water at 93.2 degrees that flowed constantly across their necks
The other set had liquid at minus-4, but also a valve that could control flow
Researchers told participants to open valve, thereby releasing flow of extremely cold liquid, whenever they felt their neck had become
uncomfortably warm during exercise
They could turn valve off and on as needed
Researchers monitored them through exercise and for one hour after exercising, telling them to keep their neck temperature comfortable
during recovery.The women wanted more cooling than men, despite similar overall changes in body temperature, and used cold liquid more often
as evidenced by women's more frequent use of antifreeze liquid while exercising
Vargas theorizes that women have more subcutaneous fat than men, as well as greater perceptual responses to temperature changes.What was
especially striking, however, was what scientists saw during recovery or cool-down
After a vigorous workout or competition, most athletes take time for a cool-down (also sometimes called a warm-down), an easy exercise that
allows body to return to a resting state
After a hard run, for example, a cool-down might involve a slow jog or walk
(Not to be confused with a warm-up, an exercise that prepares muscles for a more vigorous workout.)During cool-down, skin temperature in men
fell gradually and returned to normal within an hour
In women, however, skin temperature fell more rapidly, returning to normal within 10 minutes
Logically, this should have reduced need for neck cooling in women; but women in study continued to release cold liquid, perhaps because
their core temperature (body's internal temperature, that is, temperature of their circulating blood) remained elevated, Vargas said.The
scientists studied young healthy men and women and did not take into account hormones or menopause in women, thus "it would be remiss to
conclude that there aren't other factors involved," Vargas said, conceding that "considering wealth of knowledge surrounding impaired
temperature regulation during and post menopause, it is likely that these findings would differ greatly for women in these
categories."Further research should include these women, she said.Edward Laskowski, co-director of Mayo Clinic Sports Medicine, who also was
not involved in study, said he found results surprising
"I would have thought that women would be making themselves warmer instead of cooler - for example, guys always want to lower air
conditioner, and women raise it," he said.Because study sample was small, Laskowski said it would be difficult to extrapolate findings to a
Nevertheless, he said, "it points out some interesting trends, and, as authors point out, it can provide foundation for future studies that
look at thermal response in disease states, such as multiple sclerosis."Both elite and recreational athletes engage in thermal behavior,
although elite athletes probably have a better understanding of their limits and their ability to push their bodies to extremes, Vargas said
"Nevertheless, we often see elite athletes coming off field, or running by a water station and dousing themselves with water on a hot day,
in an attempt to cool themselves," she said.During cool-down, skin temperature in men fell gradually and returned to normal within an
hour.Photo Credit: iStockVargas said she believes that a better understanding of thermal behavior during sports - with goal of improving
thermal comfort - potentially could provide competitors with a performance edge
"Athletes who perform multiple bouts of high intensity exercise, which result in compounding increases in core temperature, may benefit
