4 Tips to Survive and Adapt to the Heat

by James Hubbard, MD, MPH

Big news for the Northern Hemisphere. Summer will officially be here June 21. If you’re in the Southern Hemisphere, I’m a little early (or late). You might want to take a look at my cold-weather posts. But for us northerners, the heat is on. For as long as I’ve practiced medicine, whether in Mississippi or Colorado, I’ve known that in those first few hot days I’ll be treating some otherwise healthy people for heat-related problems. In fact, just the other day, I saw a man in his early 20s with chest pain, headache, and just feeling awful. He’d been working on a roof. He’s done it for years with no problem. But around here, it suddenly went from a daytime high in the mid-70s to a high in the low 90s. He hadn’t had time to acclimate.

Fortunately, he got out of the heat as soon as the symptoms hit. With some water and cooling off, he was feeling fine in a few hours.

Probably, in a few weeks he’ll be working in the same temperature with no such symptoms. Why?

He’ll be acclimated.

No matter how many years you’ve been working or living in the heat, your body has to re-acclimate to it each year. So with sudden changes, such as heat waves, everybody suffers.

Other sudden changes could be maybe the electricity goes off. That’s a disaster in my book. Or maybe you’re vacationing to a hot spot. Any sudden change of heat—say 10 degrees Fahrenheit or more—will require time for your body to adapt.

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Adapting to the Heat: How Your Body Acclimates

When the weather gets hotter, your body adapts in a few ways:

1. You get more efficient at sweating. Sweat cools your skin. The faster it evaporates, the more the cooling, so a little breeze can help (to an extent). On the other hand, humid weather can slow the evaporation down.

Once your body adapts to more heat, it begins to produce more sweat, and you start sweating at a lower temperature. The “new sweat” also contains less salt concentration, so you don’t lose as much sodium. And this less-concentrated sweat evaporates faster, cooling the skin quicker.

2. Your blood gets circulated more efficiently. Your body also adapts to the heat by putting a bit more fluid into your blood. This increases the blood’s volume so that with each heartbeat, more gets pumped out. Your heartbeat slows down in response, which reduces your body’s workload, decreasing your metabolism a bit. Metabolism produces heat. So, voilà, your body is now producing less of its own heat, and the external heat isn’t quite so overbearing.

One thing to remember, though, is your body can’t accomplish these adaptions in a split second. In fact, it takes a day or so before it even starts trying and about two weeks for the acclimation to complete. During this time, it will only know to start working on these processes if it’s exposed to a minimum of about two hours of that extra heat every day.