sun shining through branchesby James Hubbard, M.D., M.P.H.

Where I used to live, in Mississippi, it got hot in the summer. Really hot, and humid. Going outside was like entering a sauna. Many of my patients worked outside. Others worked in large metal buildings with no air-conditioning. Each year, I would have to treat several for hyperthermia. The surprising thing, though, was how few.

A big reason is they worked yearlong that way. The seasons change gradually, and their bodies adapted. Even then, though, when it got in the high nineties their bodies needed help. The smart ones had learned the tricks on how to survive the heat.

How You Adapt to the Heat: Sweat, Blood and Oxygen

Our bodies adapt to the heat in several ways:

  • We sweat more. Sweat evaporating from skin is a great cooling mechanism. To survive the heat our bodies double their sweat production and start sweating at a lower temperature.
  • Our sweat starts containing less salt, so there’s less depletion.
  • Our heart becomes more efficient, pumping more blood per beat. That blood circulates from our core to our skin surface for cooling.
  • Our cells use oxygen more efficiently. Our metabolism slows, and so does the heat it produces.

These body adaptations are called heat acclimatization, and it takes a week or two.

So a sudden heat wave can catch our bodies by surprise. Enter the tricks on how to survive.

How to Survive the Heat If You’re Not Adapted

If you work outside:

  1. Drink a couple glasses of water, juice, or sports drinks per hour because dehydration makes hyperthermia worse. Heavy laborers need as much as a quart or two per hour. It doesn’t have to be ice cold. In fact, that can cause stomach spasms. If it’s water only, add a teaspoon of salt to the first couple of quarts per day. Limit your caffeine, sugary drinks, and alcohol, as they actually dehydrate you worse. And caveat: If your doctor has suggested limiting your amount of fluids or salt, get his or her advice on what to do.
  2. Do the heavy work before 10 a.m. and after 4 p.m.
  3. Take frequent breaks in the shade. Fan a little. More about that later.
  4. Wear loose, breathable clothes.
  5. If you’re going to be in the sun a lot, don’t forget frequent suntan lotion, and consider a wide-brim hat.

If you’re inside with no air-conditioning:

  1. Open windows and use a fan. Good air ventilation is essential.
  2. But remember, when the heat gets in the high nineties, fans may make you feel more comfortable but cannot cool off your body temperature. Also, a high humidity can make it difficult for the sweat to evaporate. This can be especially dangerous for people whose bodies don’t adapt as well anyway, like elderly people, kids younger than four, and people with a chronic illness or who are being physically active.
  3. What does work is a cool midday shower, bath, or sponging.
  4. It’d be great if you could visit an air-conditioned facility (mall, senior center, adult day-care) during the hottest part of the day.
  5. Check on your at-risk family, friends, neighbors twice a day. Make sure they’re drinking fluids and look okay.

In fact, monitor yourself and your co-workers for signs of getting too hot also. I tell you what to look for and do in future posts.

Does anyone have any other suggestions for how to survive the heat?