To Beat the Heat, Learn to Sweat It Out

[Ryan]

Nothing new in this article but a good reminder as we work our way through the hottest part of the year. A few select quotes:

It may seem like a brilliant idea, then, to pour water over your head to cool down. That is what Floyd Landis did during a grueling ride on a hot day in the Alps during the 2006 Tour de France.

And last month, on that balmy Saturday, amateur runners used the same trick, dousing their heads, in an 8-kilometer race in Moorestown, N.J. Town residents also squirted runners with their garden hoses.

It is a useless ploy, said Samuel N. Cheuvront, another researcher at the Army institute. “Sweat must evaporate to provide cooling,” he said. “Dripping does not help.”

In fact, he added, if you get too wet you risk hidromeiosis, when sweat pores become blocked, which makes you even hotter.

(Note: How nice to see them use a drug cheat whose appeal was just recently denied as an example here. Couldn't find a better/cleaner example?)

Cold and humidity stresses the body less; you heat up less when it is cooler. Relative humidity may be greater on cool mornings, but what really matters for sweat evaporation is water vapor pressure. And water vapor pressure is lower when the air is cooler, meaning sweat evaporates faster.

Dr. Cheuvront said that if you have to choose between exercising in the morning when it is 60 degrees and 80 percent humidity, or in the evening when it is 90 degrees and 50 percent humidity, choose the morning.

Yet as challenging as heat and humidity are, people can acclimate. Blood volume expands, which reduces the strain on the heart from the increased demand for blood flow to the skin and muscles. And sweating increases — people who are heat adapted sweat sooner and more profusely, allowing their bodies to cool more efficiently.
...
Some people naturally adapt to heat much more than others. But Dr. Cheuvront said he had never come across a person who did not adapt at all.

The key to acclimation, he said, is to exercise in the heat daily and to be sure you are sweating profusely — wearing extra layers of clothing can help if you are exercising indoors or in cooler weather. Given a choice between spending more time in the heat but exercising less intensely, or less time and exercising more intensely, it is safer to choose to go longer and work less intensely, he said.

But no matter how much you train in the heat, it will never be easy, athletes and researchers say. So perhaps the best strategy is to just accept discomfort and slowness.

“Heat is the X factor,” Ms. Roth said. “Sometimes you have to just forget it and move on.”

[sueruns]

I think the article forgot to add "For most people" on a lot of the suggestions...or "normal, healthy people".   especially when talking about being better off running in mornings in higher humidity.   

[Ryan]

I guess I normally consider the "for most people" to be assumed in those statements but I see your point.

[sueruns]

I guess I normally consider the "for most people" to be assumed in those statements but I see your point.

I'm thinking of asthma, specifically when the article suggests they run when it's most humid.   I can't even fathom running in FL in the early morning