How to exercise in Singapore's heat without succumbing to it

IT’S TOO DARN HOT, SO BE STRATEGIC

When we exercise, we generate internal heat, which our bodies shed by sweating and shunting warmed blood away from our cores and toward the skin. If ambient temperatures rise, though, this process falters. Body heat builds up. Our hearts labour to send additional blood toward the skin. We glisten with sweat, and the same run, stroll or ride that felt tolerable during cooler weather now drains us.

To sidestep these conditions, we can move our workouts indoors, into air-conditioned comfort, or schedule them strategically. “I would always recommend the morning,” especially for city dwellers, says Oliver Gibson, a senior lecturer in exercise science at Brunel University London and lead author of the review.

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“In an urban area, it is likely that the concrete will have retained a high amount of residual heat that will radiate back” at exercisers later in the day, he says. Unshaded sidewalks similarly will be hotter than parks and leafy pathways.

AIM FOR ACCLIMATISATION

We also should accustom ourselves, slowly, to unfamiliar swelter, Dr Gibson says, a process known to exercise scientists as acclimatising, which involves working out sometimes, by choice, when the day is warmest. 

This approach helps to condition our bodies to better cope with the heat. Once acclimatised, we will sweat earlier and more abundantly than before, dissipating internal heat better and leaving us feeling bouncier and less fatigued.

Acclimatising should be gradual, however. To start, slather on sunscreen, fill a water bottle, head outside after about 10am, when temperatures intensify, and try to complete a gentler version of your standard workout, says Carl James, a senior physiologist at the National Sports Institute in Kuala Lumpur, Malaysia, and co-author of the review. 

If you usually run for 30 minutes, for instance, maybe jog for 20, and monitor how you feel. If your heart seems to be racing, he says, or you feel lousy, “slow down”.

After a few acclimatisation sessions, you should notice your clothes and skin are drenched, Dr Gibson says. Congratulations. “Earlier and more profuse sweating is a great sign that heat adaptation is taking place,” he says.

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Most of us acclimatise after about five to 10 hot workouts, he adds, although women, who tend to sweat less freely than men, may require an extra easy session or two to be fully prepared for harder workouts in the heat.

TAKE A WARM SOAKING

After each acclimatisation session, head for the showers, but dial up the heat. Standing under a warm shower spray or soaking in a hot bathtub for 10 minutes or so after a sweltering workout prompts our bodies to continue acclimatising, Dr Gibson says. “It extends the stimuli for heat adaptation,” he points out, “and is therefore welcome and beneficial”.

SLURP A SLUSHIE BEFOREHAND, CONSIDER COLD UNDERWEAR

An icy beverage before a hot workout “will help with hydration and provide a combination of perceptual and actual cooling”, Dr Gibson says. Aim to drink about 16 ounces (470ml) of cold fluid 20 minutes or so before you head out. Drinking closer to the session’s start could cause stomach upset during your workout.

Slapping a cold washcloth onto your neck, donning an ice vest or slipping into athletic undergarments that have spent the night in the freezer likewise can up coolness (if not comfort) during hot-weather exercise. 

So can a gentle misting of chilly water on your face or licking an ice pop, says Ashley Willmott, a lecturer at Anglia Ruskin University in Cambridge, England, and another review co-author.

But these techniques can be risky, too, he cautions, because the cooling effects are limited and short-term, and potentially deceptive. “We sometimes see people cool before exercise, feel great, then head out too fast or hard,” he says, winding up prematurely winded and possibly on the cusp of heat problems.

RECOGNISE SIGNS OF OVERHEATING

If you feel nausea, headache, dizziness or cramping during a hot workout, slow down or stop and hunt for shade, Dr Gibson says. These could be signs of incipient heat illness. 

Unfortunately, heat illness also clouds thinking, says Neil Maxwell, a lecturer in environmental physiology at the University of Brighton in England and the review’s senior author. “Your judgment becomes impaired,” he says, and you may not realise you are overheating.

He and his co-authors strongly recommend exercising with a partner in the heat. If either of you starts to feel “seriously hot or shows signs of cognitive dysfunction”, he says, such as sudden confusion, get off the path, under a shady tree or awning, and call for help.

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“Rapid cooling is essential within the first 30 minutes” of such an episode, Dr Maxwell says. Immediately applying a cool cloth could help to start lowering body temperature.

You might also protect yourself and your training partners by the simple expedient of rejiggering your routes, Dr Gibson says. “On hot days, do shorter loops” than normal and include “a dedicated water station,” he suggests, such as a public drinking fountain. 

Refill your water bottle there or stick your head under the flow each time around. Plus, “if you are feeling the heat,” he concludes, running in short loops “makes ending the session early more realistic”.

By Gretchen Reynolds © The New York Times

This article originally appeared in The New York Times. 

https://www.nytimes.com/2021/06/23/well/move/exercise-heat-advice.html