Aug. 23, 2007 -- It's that time of year. Sizzling, steamy and sticky summer temperatures can usher in sweat waves and many people dislike it.
"Most people don't think very positively about sweat," said Penn State University professor Nina Jablonski.
Some find sweat unseemly, uncomfortable and unpopular. But, it does have some proponents.
There is even a Web site celebritysweating.com devoted to what it calls "excessive people, excessive sweating."
"If you are a copious sweater you should be proud of it. It is not something to hide or conceal," Jablonski said.
Yet, excessive sweat can impact others' perceptions of a person. Some say sweat helped lose an election for Richard Nixon, when he visibly perspired in a debate against John F. Kennedy.
Even if some dislike it, a scientific reason for sweat exists.
"Basically we can't keep cool without sweating," Jablonski said.
Sweat is the body's main coolant. Whenever a person begins overheating, either from exercise or high temperatures, the brain says "start sweating." It is the evaporation of the water from your skin that helps cool the body off.
The average person has about 2.6 million sweat glands and while working out, the average person can sweat out a gallon in an hour. Professional athletes can sweat twice that amount.
But perspiration isn't limited to heat or exercise. Some people sweat when they are nervous and that is because the sweat glands are connected to fight-and-flight mechanisms.
One study found men sweat more than women because their glands have greater capacity.
There is growing research now into sweat, a sort of sweatology. The Energy Department built ADAM, a sweat mannequin to study how to reduce automobile fuel consumption by cutting down air-conditioner use.
"When we pull him out of a car, his backside is wet, just like a person in traffic," said John Rugh of the National Renewable Energy Lab.
And in Texas researchers are using a "sweat suit" developed by NASA.
"We're trying to learn why sweat glands become more sensitized under certain conditions," said Craig Crandall of Southwestern Medical Center.
So, the science of sweat, let's just say, it doesn't stink.