On the sultry, swampiest summer days, you will no doubt be asked if shirtless walking is the best way to beat the heat. But before you think about how to equip or undress, you should understand what happens to your body in the heat.
"When you exercise, you use energy stored in your body to do the work," explains Samuel N. Cheuvront, Ph.D., a research physiologist who deals with fluid balance and endurance training. "But only about 20 percent of the total energy that we generate during sport actually goes into physical work. The rest is converted into heat."
Your body has a limited capacity to store this thermal energy. When your brain senses that your body temperature has risen, it triggers two reactions: it directs more blood flow to the skin, where increased vasodilation – an expansion of the blood vessels on the skin surface – prepares your body to dissipate heat, explains Chris Minson, professor for Human Physiology at the University of Oregon, examines the heat acclimatization reactions in athletes. At the same time, your brain signals the millions of sweat glands in your body to press water vapor through your pores onto your skin, where it evaporates. It takes energy to convert this liquid into gas. In this way, your body is freed from excess heat, he explains.
Tips for heat acclimatization: preparing for races in warm weather and training outdoors
This evaporation process is crucial. If you wipe off the sweat or it just drips from you, it will not take any heat with you. As every runner knows, it's not necessarily the heat that makes running so difficult in the summer, but the humidity. The wetter it is, the more water vapor is in the air, Cheuvront says. And "if the water vapor pressure in the air is higher than the water vapor pressure of your sweat, your sweat cannot evaporate – it just drips," he explains. And so all of the heat that you generate builds up in your body without being released.
With these hot, humid runs, "the less clothing you wear, the more opportunities for heat to evaporate between your skin and the air," says Cheuvront. (However, if it is very swampy, you cannot reconcile heat generation with heat loss – even if you are running naked. In this case, you can either decrease your intensity to produce less heat, or you can look for something active cooling like running through sprinklers.)
A pleasant breeze and / or the natural airflow you create while driving – called convection – can improve the efficiency of evaporation even in humid conditions. "When a breeze blows over your skin, the humid air is pushed away from you, so the air near your skin is drier," says Minson.
Choosing more skin exposure is generally the best choice if it's not too sunny or you're walking in the shade. However, if you're running at noon on a cloudless day, adding a layer over your skin can be beneficial. "If there is more direct sun, this solar radiation can warm you up a lot," says Minson – even if the air temperature is not that high. Under these conditions, you want to protect the skin not only from sunburn, but also from the heat of the sun. Wearing light-colored clothing (no dark colors!) Can help reflect or block some of these heat waves, he adds.
Heatwave training: how to train in hot weather
If you are aware that you are running shirtless in public, this is cool. Although all clothing is to some extent insulated (trapping air and preventing evaporation), so much progress has been made in fabric technology that you can easily find a light shirt that won't pull you down. “You want to wear clothing with very little insulation. We call it a low CLO, ”says Cheuvront. “It should be very permeable to absorb sweat easily and to evaporate this sweat easily. The surface of the clothing is actually cooled by the evaporation of sweat, which in turn keeps the skin cool. “Look for words like quick-drying, sweat-wicking and breathable.
Remember: "When it comes down to it, there is nothing that improves our sweating ability better than our own skin," says Minson. And it's hard to be shy when you take off your shirt when you feel the sweet relief that comes with all the fresh air on your skin.
If you want to put on clothes, try these lightweight, breathable walking utensils.
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Ten thousand distance tank
Micro eyelets provide ventilation throughout the tank. It minimizes clinging, drapes over your body for minimal chafing, and is treated with silver ions to relieve the stench. t a fan of tanks? Ten thousand also makes a spacer shirt ($ 54; ten thousand.cc) from the same material and the same sage green color.
($ 54; ten thousand.cc)
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Janji Men's 8 "2-in-1 Traverse Short
You don't need short thigh-length shorts to stay comfortable. Janjis Traverse Short combines a sweat-wicking brief with an 8-inch inner seam for modesty with a woven shell short. Two elastic pockets and a bungee with a loop offer numerous storage solutions (this loop can be used to hold the keys securely or a shirt if you should be walking without a shirt).
($ 72; janji.com)
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Mission Cooling Gaiter
Neck gaiters are becoming increasingly popular due to the COVID-19 pandemic. They are lighter, more breathable and quicker to dry than bandanas, and can be pulled up to cover your mouth and nose when you pass pedestrians and other runners. (Pro tip: wear a cap and stick the top of the gaiter into the rear opening to keep it on its own.) Mission has a UPF 50 rating that blocks up to 98 percent of UV rays. When the weather is exceptionally hot, you can wet the gaiter, wring it out, and then snap it into place to activate cooling technology: in less than 30 seconds, it cools to 30 degrees below average body temperature. When you do this, just hold it around your neck (wetting makes it impossible to breathe deeply).
($ 20; mission.com)
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