The first significant heat wave of the summer is expected to hit much of the United States this weekend, impacting regions from the Midwest to the East Coast. Temperatures are forecasted to be well into the 90s, according to the National Oceanic and Atmospheric Administration.
So if you're planning to be outside, whether it's for fun or for work, take measures to stay cool and protect yourself against heat-related illness, says Ashley Ward, director of Duke University's Heat Policy Innovation Hub.
If there's a heat advisory in your area, you'll want to avoid outdoor activities. But even if there isn't one, take caution when outside on a hot day, she says. " It's one of the big misconceptions about heat to think, 'I'm only in danger when there's a heat wave occurring."
Extreme heat is the No. 1 weather-related killer in the United States, according to NOAA and experts say its risks are likely underestimated It can cause heat exhaustion, "your body's way of telling you to get out of the heat immediately," or heat stroke, a life-threatening illness that can occur if heat exhaustion isn't treated, says Dr. Renee Salas, assistant professor of emergency medicine at Harvard Medical School.
Warmer-than-normal temperatures are expected throughout the summer, according to NOAA. Heatwaves and longer, hotter summer seasons are intensifying because of human-caused climate change, according to the World Health Organization.
Here's how to plan for outings in hot weather.
Don't just rely on the air temperature. Check the heat index.
Before starting your lifeguard shift or going to that barbecue, take a moment to check the heat index. It includes humidity as well as the air temperature, giving you a more accurate read on how hot it will feel outside, Ward says.
Also take note of the cloud coverage, wind flow and time of day you plan to be outdoors. When it comes to heat-related illnesses, "if it's a very humid day and there's no wind speed, then you are more at risk, even if the air temperature is lower," Ward says. For example, a very humid 88-degree day with no wind could be more dangerous than a 94-degree day with low humidity.
If you can, plan outdoor activities earlier in the day, before the hottest time of day in your area. "Three to 5 p.m. in the afternoon is one of the most dangerous times of day," says Ward.
Consider what you're wearing.
Whether you're headed to the pool or going for a walk, wear lightweight, breathable garments. Opt for cotton or linen fabrics, which have big pores in their woven threads that allow for air circulation, or moisture-wicking materials, which draw sweat away from your skin, helping it to evaporate more quickly, Ward says.
Choose loose-fitting silhouettes, Salas says. If your clothes are too tight, the sweat on your skin can't evaporate, which is key to keeping your body cool. "I'm sure people don't love sweating profusely, but sweating is actually our friend when it comes to heat."
Don't forget sunscreen and a wide-brimmed hat to prevent sunburn, says Alyssa Provencio, a professor at the University of Central Oklahoma who researches emergency and disaster management.
Opt for shady, natural environments.
Your location can make a big difference in how hot it feels. Dark surfaces like asphalt tend to absorb more heat than natural environments. And because shaded areas have less solar exposure, they can feel much cooler. "You can reduce the temperature around you 10 degrees or more by just moving to an area that's shaded."
So if you're a dog walker and it's a hot day, walk those pets down a tree-lined park or a wooded trail instead of the sidewalk. Or if you're headed to the pool, bring a sun umbrella or a pop-up tent to provide some coverage, Provencio says.
Know the symptoms of heat exhaustion.
If you're out with a group of friends on a hot day, keep yourself and others safe by looking out for signs of illness among each other. "Somebody may notice something in you that you don't notice," Salas says.
Heat exhaustion is your body's warning sign that you're starting to overheat, Salas says. Generally, symptoms include sweating more than usual, weakness, dizziness, fainting, pale skin, nausea, vomiting and fatigue.
Pay special attention to seniors, children, people with certain pre-existing medical conditions, and people on commonly prescribed medications to help manage blood pressure and mental health conditions. They are at higher risk of heat-related illnesses, Salas says.
If you or someone you know is experiencing signs of heat exhaustion, Salas recommends going into an air-conditioned room. Provencio recommends public libraries because they're free and open to everyone.
If you're still experiencing symptoms of heat exhaustion after removing yourself from the heat, seek medical care.
Water is your friend.
On hot days, bring water with you wherever you go. Salas says drinking water can help your body produce more sweat.
Beware of drinking alcohol on hot days, she says. You may be tempted to crack open a cold beer on the beach, but it's a diuretic that can dehydrate you and impact your ability to sweat and cool yourself.
If you're feeling hot and need a quick way to cool down, you can also submerge yourself in a body of water. If that's not feasible, dunk your feet and arms in cold water, Ward says. It can "lower your core body temperature."
Lower your body temperature with cooling towels.
If you're feeling hot, put an ice pack, a wet towel or a cooling towel, which stays extra cold when they get wet, on the back of your neck, under your armpits and on your groin, Ward says.
"Some of the body's major blood vessels closer to the skin live there," Salas says. And when you put something cold on those areas, "it can help cool the blood running through them."
Don't forget to take breaks.
"If you're being active outside, whether that's working, exercising or playing sports, as you work, your muscles are producing heat," Salas says. So take a moment to stop producing heat and cool down in the shade or an air-conditioned room.
On those breaks, remember to drink more water too, Provencio says.
This story was edited by Malaka Gharib. The visual editor is Beck Harlan. We'd love to hear from you. Leave us a voicemail at 202-216-9823, or email us at LifeKit@npr.org.
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