Thursday, July 3, 2008


Gina Kolata takes a look at heat, humidity and the necessity of sweating during workouts. It goes without saying that sweating is vital to keeping core temperatures low and our body as close to homeostasis as possible. The most important part of the sweating process is the evaporation of the sweat on your skin. It is the act of evaporation that cools your off. I can attest to this – spending four years of college volleyball preseason in a hot and humid gym. Without a breeze to cool off, the sweat just stays there and you continue to get hotter. I’ve been known to wring out my shirt midway through practice.

Thankfully, since I've moved to SoCal, I've had to deal with a lot less humidity than the East Coast. This summer's weather report from Cranky Fitness sounds all too familiar from my days growing up in New England. California is hot, but at least it's dry.

Regardless, the fact that I sweat so much is a good thing. I am, what the article calls, a “heat adapted” or as I like to think of it, heat adept. This means by body has the ability to adjust appropriately to the temperature.

And how does one study people’s heat adaptedness? Why, they participate in this grueling experiment:
For example, if you are not acclimated and run for an hour in 98-degree heat, your core temperature may go up to 103 degrees, bordering on the danger zone, said Craig Crandall, who studies heat acclimation at the University of Texas Southwestern Medical Center in Dallas. But if you are acclimated, your temperature might be 101 degrees after an hour long run, which is well within the safety zone. Acclimation takes at least five days, Dr. Cheuvront found. He first asked participants to walk on a treadmill for 100 minutes in a room that was kept at 100 to 120 degrees.

On Day 1, Dr. Cheuvront said, they usually last 30 to 45 minutes. Then, he added, they will either request to get off the treadmill; collapse; or reach the safety-limit core temperature of 104 degrees, at which point they are stopped. By Day 5, just about everyone lasts 100 minutes.
It is possible to adapt even more. Dr. Cheuvront’s subjects continued to improve when they walked on the treadmill in that hot room for five more days.

So here’s the sweaters (not the winter ones) like me, who drip and sop after a good workout. Think of it not as sweat, but as victory juice.

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