October 8th, 2010
04:16 PM ET
The idea that women's "glow" is somehow different from men's "sweat" has new support: A Japanese study finds that women have to work harder than men while exercising in order to start sweating.
Moreover, men are more efficient at sweating, say scientists at Osaka International University and Kobe University in Japan.
The study, published in the journal Experimental Physiology, looked at 37 people, which included 20 females and 17 males. Of them, 10 of the females and eight of the males were trained. "Training" meant that these subjects had participated in endurance sports for more than six years, whereas "untrained" people in the study had not done any regular physical activity in the previous three years, with the exception of gymnastics lessons. None of the females had taken oral contraceptives, which might have altered the sweating results.
Participants cycled at 35, 50 and 65 percent of their maximal uptake of oxygen for an hour, with relative humidity of 45 percent.
Researchers found that trained participants had a greater average local sweating rate on their foreheads, chests, backs, forearms and thighs than untrained participants. But there was a striking gender difference also: Men benefited more from their training experience in their sweat production than women.
Untrained females had to work harder or have a higher body temperature in order to achieve a maximal activated sweat gland response, the scientists found.
The scientists suggest that increases in the sweat gland's response to physical training was smaller among trained females than trained males. This could be because men have higher testosterone levels than women, and testosterone may enhance the sweating response.
An important limitation is that this study did not measure testosterone levels. Also, it only included 37 people.
The findings suggest that women especially should take care when a heat wave is about to hit. But everyone can benefit from regular exercise in terms of the way their bodies respond to heat.
Sweat may be smelly sometimes, but there are good reasons to want to perspire.
Perspiration is mostly water and salt, with trace amount of electrolytes, which help regulate the fluid balance in the body, according to the Mayo Clinic. This fluid comes from the eccrine glands, which get stimulated by the automatic nervous system when your body temperature goes up. This kind of sweat cools the body as it evaporates on the surface of the skin.
But there is also another kind of sweat, which comes from the apocrine glands. This is the type of sweat is associated with emotional stress, and the accompanying odor comes from bacteria breaking it down.
Future research would look at the effectiveness of different kinds of sweat, and also examine how the sweating response relates to reproductive hormones, study authors said.
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