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How to avoid heat-related illnesses


Excessive heat advisories are in place across the U.S. from the Pacific Northwest to the southern tip of Florida. So if you want to spend time outdoors, you need to avoid some common mistakes that lead to heat-related illness. Here's NPR's Allison Aubrey.

ALLISON AUBREY, BYLINE: Dr. Neil Gandhi has seen plenty of heat exhaustion in his ER. As an emergency medicine doctor at Houston Methodist Hospital in Texas, the heat can be a serious health concern, but he says people tend to underestimate the risks.

NEIL GANDHI: I think the most common mistakes really kind of fall into two categories. One is what I call too much, too soon.

AUBREY: When a heat wave comes along, most people are accustomed to working and spending most of their days indoors in the comfort of AC.

GANDHI: And all of a sudden on a Saturday or Sunday, they opt to spend six, seven hours outdoors. These individuals are - they're very sensitive because their bodies are not acclimatized to handle the stress.

AUBREY: The good news is that our bodies can acclimate. And what it takes is spending time outdoors each day in the heat before you decide to set out for a long day of cycling, hiking, golfing, or even tackling your home improvement or gardening project. David Eisenman is a physician and researcher at UCLA. He explains how our bodies adjust after repeated exposure to the heat.

DAVID EISENMAN: One thing that happens is that our body starts to learn how to sweat sooner. Also, the blood flow to the skin improves, and when there's more blood flow, it carries more heat. So it can get the heat out of the core of your body, cooling your core temperature better.

AUBREY: He says there's no magic number of hours of exposure that it takes to adjust. It's more of a continuum. So bottom line - the more time you spend in the heat, the more acclimated you can become. Another common mistake people make is failing to pre-hydrate before they go out in the heat. Sounds kind of obvious, but lots of people underestimate. And in the extreme heat you may start to become a little dehydrated before you sense thirst. Eisenman says eight cups a day of water is reasonable on a typical day, but being outside in the heat, you may need more.

EISENMAN: Most people aren't hydrated enough as it is, so I would double that on a day when you're exposed to a lot of heat. I would be making sure that you're peeing frequently and that the urine is pale clear, and that's when you know you're hydrating yourself correctly.

AUBREY: Another way to protect yourself is to find out if the medicines you take can make you more vulnerable to the heat. Common blood pressure medications taken by millions of people can have a dehydrating effect, making them more susceptible to heat exhaustion. And when it comes to a really simple thing you can do on a hot day, the way you dress can make a difference, says Wafi Momin, a cardiologist at Memorial Hermann Health System in Katy, Texas.

WAFI MOMIN: As far as being outdoors and what to wear and in terms of color, I would seek lighter colors because those tend to reflect heat rather than absorb heat compared to darker colors such as your blacks and dark blues, and then loose fitting clothing on top of that.

AUBREY: He says the first signs of heat-related illness can go unrecognized or even ignored - things like slight fatigue, dizziness, nausea or a headache.

MOMIN: Those are the telltale signs of heat exhaustion creeping in.

AUBREY: That's the way of your body telling you you need to cool down. So Dr. Momin says don't ignore the signs.

MOMIN: The worst of the symptoms can come on very quickly without realizing it. And all of a sudden, you know, your body's overheating to a point where you won't really be able to drink enough fluids at that juncture to kind of reverse what's already going on.

AUBREY: That's how people end up in the ER. So he says be safe rather than sorry by acclimating, planning ahead to stay hydrated and then recognizing when it's time to get out of the heat.

Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

Allison Aubrey is a correspondent for NPR News, where her stories can be heard on Morning Edition and All Things Considered. She's also a contributor to the PBS NewsHour and is one of the hosts of NPR's Life Kit.