Even though it was a hot, humid August morning, I still wanted to do my daily walk around Hermann Park before work. But I got out there later than usual; by the time I was in the homestretch, it was almost 10 a.m. The sun was pounding down so I decided to cut across the zoo’s parking lot.

Marching along, I started to feel faint, but told myself to keep going. I was almost there. By the time I got to the car, my skin was hot pink and sweaty. I blasted myself with A/C and took a cold shower when I got home, but the water didn’t feel cold and I was still pink even after the shower. At work, everyone asked what was wrong. I developed a terrible headache and took some Advil. By the next day, I felt better. But ever since that morning, I have feared the sun.

I never went to the doctor—typically—but have always been curious about exactly what happened to me that day, which is why I recently called Dr. Jeffrey Kalina, associate medical director of emergency medicine at Houston Methodist, to see if he could shed some light on the matter. 

“It doesn’t sound like you had a heatstroke,” he told me, “but you clearly had heat exhaustion, which is part of the spectrum of heat-related illness,” an illness brought on when the body’s natural cooling mechanism is disrupted. “When the wind blows on sweat it feels good, and that is how the body cools. During the course of heat exposure, heat illness, and heatstroke you get dehydrated, and you lose the ability to sweat.” 

Furthermore, the body’s cooling system can easily break down in super-humid climates like ours. “Unfortunately, once the humidity gets to around 75 percent,” he said, “it’s not as effective.” When heat illness sets in, it’s best to get to the shade, or inside to the A/C, and to remove tight clothing, drink plenty of water, and use an ice pack. In the case of heatstroke, of course, head to the ER—it can cause permanent damage to the brain. 

So how are we supposed to stay fit through a brutal H-Town summer? “Hydration is key,” said Kalina. If you’re working out outside, do so in the morning or evening. “When mosquitos are out,” he said, “is when you want to be exercising.” Don’t forget to wear hats, sunscreen, and protective clothing, including “wicking sweat” clothing that pulls moisture off the body. And if possible, get your exercise indoors at one of the many, many spots around town there for that purpose, which, it just so happens, we explored for this issue, your comprehensive guide to working out and staying cool in the months ahead. —Catherine Matusow

In This Feature:

Beat the Heat: Four Summer-Friendly Exercise Alternatives

Workouts delightful, even when the weather outside is frightful

05/01/2014 By Kerry H., John Lomax, Katharine Shilcutt, Chris Abshire, and Catherine Matusow

Staying Cool in the Pool

From Schlitterbahn to splash pads, a guide to the best watery oases around

06/02/2014 By Peter Holley

Crossfit Confidential

Are the high fees and endless burpees really worth it?

06/02/2014 By Michael Hardy

Shirts (and More) You Won’t Sweat Through

Moisture-wicking technology is almost as good as air conditioning.

06/02/2014 By Sarah Gabbart

The Men’s Locker Room: a Survival Guide

Tip 1: Stop doing naked lunges.

06/02/2014 By Jeff Balke