Scientists studying people working under super-hot conditions have learned a lot about how the body handles heat. Beyond the basic advice of staying hydrated while avoiding sugary drinks, caffeine and alcohol, here are some evidence-based strategies for coping with our overheating world.
Be in shape – Being aerobically fit increases your ability to handle heat. A workout is like a mini-session of heat stress. “With heat acclimation as well as with training, your resting core temperature decreases,” Wright said. “As your temperature increases with exertion, heat and that sort of thing, it takes a longer period of time before your temperature reaches high levels, which are of concern.”
Go for the green – As anyone who’s emerged from an air-conditioned car to set foot on sticky-hot asphalt can attest, “heat islands” are a real thing. Under the blazing sun, roofs and pavement can reach temperatures from 50 to 90 F (10 to 32 C) higher than the air temperature. For your own personal heat island escape, head for any patch of green you see, ideally one with some trees for shade. Plants not only block sun; they act like living air conditioners. “When the plant takes moisture up from the soil and exhales it through the leaves, you have evaporative cooling,” explained Stan Cox.
Take a rest – Feeling overheated? Not only should you head for the shade or an air-conditioned room, but also you should spend longer there than you think you need to. Even after you’re out of the heat, your core temperature will keep inching up before it goes back down. When you’re feeling the effects of heat stress, regular breaks that are at least 15 minutes long are needed to reduce the increases in body temperature and cardiovascular strain, Wright said. Try to get to a cool or shaded area and allow time for your breathing and heart rate to slow to normal.
Leave your sweat on your skin – The human body has evolved to cope with heat by sending more blood to the surface of the skin to dissipate heat, and by sweating. Both of these processes become more efficient in fit people and with heat acclimation. To take full advantage of these built-in systems, don’t wipe off sweat, but allow it to evaporate from your skin and cool you down, Sawka said. If you need a fast cool-down, plunge your arms into cold water up to the elbows. This trick works to pull heat out of your body efficiently because your forearms have a high surface-area-to-volume ratio.
Switch out light bulbs, and unplug – Even a single incandescent bulb can generate a significant amount of heat. Per hour, a regular light bulb gives off 85 British thermal units of heat. For comparison, compact fluorescent lights give off 30 BTUs per hour, and light-emitting diodes give off just 3.4 BTUs per hour. Devices from computers to TVs to smartphones are also potent heat sources, so shut them off and unplug them if they aren’t in use.
Get passive-cooling aggressive – A host of approaches can help you cool down your environment while using little or no energy, Cox said. People can put shades on south-facing windows, open windows at night to let cooler air flow in and close them in the morning before the day heats up, and strategically use open windows and box fans to keep air circulating, he said.
Embrace public spaces – Air conditioning may hog electricity, but it does boost human productivity. Several studies have shown that workers’ energy drags as the temperature climbs. And nothing beats AC for coping with oppressive humidity. Those who need to get some serious work done on a torrid day might search out a public library or coffee shop, where the cool environment will help you crank it out — and leave you more time for summer fun when you’re done