Tag: heat

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Jockology: exercising in the heat

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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This week’s Jockology column in the Globe and Mail is a round-up of a few recent studies on exercise in hot weather: how the brain slows you down more than the body; how acclimatization does (and doesn’t) work; and how cooling your palms can make your workout feel easier.

[…] “Slowing down in the heat could be a subconscious regulation to protect us from damage, such as heat stroke,” explains University of Bedfordshire researcher Paul Castle, the lead author of the study.

In other words, you don’t slow down because your body has reached some critical temperature. Instead, your brain slows you down to prevent you from ever reaching that critical temperature. It’s a subtle difference – but as the cyclists in the study discovered, it means that our physical “limits” are more negotiable than previously thought… [READ THE WHOLE ARTICLE]

 

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Heat acclimatization: what does it take?

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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Conventional wisdom says that we adapt to deal with heat after a week or two of high temperatures. But a study in the current European Journal of Applied Physiology suggests that it doesn’t happen automatically. These days, we spend a lot of time in air-conditioned homes, offices, cars and even gyms — so we may no longer get the stimulus we need to adjust to exercising in heat.

To test this proposition, researchers at the University of Ottawa tested a group of 8 volunteers in mid May and early September. They measured core temperature, skin temperature, skin blood flow, sweat rate, heart rate, and a few other variables during a 90-minute bike session at 60% VO2max — and found no significant differences even after a long, hot summer. The key: their subjects reported spending an average of just 18 minutes a day doing “moderate” or “intense” physical activity outdoors over the summer.

In comparison, chamber-based heat acclimation protocols known to elicit physiological adaptations require a minimum of 1 h of exercise at 50% of VO2max for ten successive days in order to elicit a physiological acclimatization.

There’s no doubt that heat acclimatization effects are real — enhanced sweat rate and greater blood flow to the skin, resulting in lower core temperatures. But you have to get out there and sweat to make it happen.