Don’t know how to break the news to you, but summer’s here. Sorry. The calendar might say it’s still spring, but whoever believes that lives in Minnesota. For the next three months we will be smack dab in the middle of the worst running weather Central Texans annually face. Our summer dynamic duo of extreme heat and high humidity can bring on overheating on a run of any length which can lead to heat stroke or exhaustion.

This is dangerous stuff which should not be trivialized. A runner of any level of ability, size or shape can be susceptible to overheating/heat exhaustion.

Overheating is really quite simple. When the body can’t cool itself adequately, it overheats. The reason we overheat is because our bodies can’t keep up with the evaporation demands of water—sweat—from our skin surface.

During a run, our bodies internal furnace heats up and we sweat. That’s a good thing. As we sweat, the body sends more blood to the skin where it is then cooled by coming into contact with the relatively cooler skin. But while running, our body is also demanding oxygen to the working muscles which means less blood will flow to the skin. When that happens, the cooling process is inhibited which is when overheating occurs.

You may not realize it, but there’s almost a tug-of-war battle being waged if you want to maintain a certain running pace. Either the blood and oxygen goes to your working muscles to keep up with the running pace demands, but you start to overheat because less blood is going to the skin for cooling. Or, the blood is diverted to the skin for cooling, but that means less blood is going to working muscles which forces you to slow down dramatically.

The cooling/evaporative process is further short-circuited by our high humidity. Even if the blood works its way to the skin and we sweat, the brutal humidity doesn’t allow the sweat to evaporate very well and thus, cool us down. Running in hot, dry weather might suck, but it doesn’t suck nearly as badly as running in hot, humid weather.

Dehydration is also more pronounced in hot, humid weather. When you dehydrate, you are actually losing fluid from the body (sweat). As you sweat, you lose water and other electrolytes. If you can’t sweat adequately, you’re in big trouble.

Here are some hints for surviving the Texas summer heat and humidity:

1. Run early or run late (before sunrise or after sunset). The humidity is higher in the morning and evening, but temps are obviously lower. The air quality is also better in the morning as the traffic is lighter. Given the choice, go early.
2. If you must run at lunchtime and temperatures are extremely hot, run inside on a treadmill. Or go for a swim.

3. Slow down. The heat slows everyone down. Don’t try to ignore the heat by thinking you can run your normal long-run or race pace. You can’t. At least not safely for very long.

4. The less you wear, the better. The more exposed skin surface, the better the evaporative process—cooling—works.

5. Wear light colored, lightweight shorts and shirts. Don’t wear cotton shirts or even heavy socks.

6. Drink. Staying hydrated won’t keep you cool, but becoming dehydrated results in an elevated heart rate. After your run, continue drinking water, sports drinks or juice until you can urinate freely and the urine is clear. (Dark urine is a sure sign of dehydration.) Cooler fluids taste better than tepid stuff. If it tastes good, you’re more likely to fully hydrate.

7. Try to run in some shady areas and near the water. (Hint: the Lady Bird Lake/Butler Trail is ideal.)

8. Grass. If you need to do a speed workout, consider running at least part of it on a grass field (such as Zilker Park). You’ll be slower running on grass, but the grass surface is certainly cooler than the reflected heat off pavement or the track.

9. Start slower. Your body heats up gradually. By starting a run with an aggressive pace, you’ll simply heat up quicker and eventually pay the price.

10. Recognize signs of overheating/heat exhaustion. Such warning signs as profuse sweating, lightheadness, nausea, vomiting, fainting are all indications of heat exhaustion. If symptoms occur, stop running. Immediate treatment should include cool drinks, ice application or jump in a pool or lake. If a body of water isn’t available, get to a cool place (such as a store, home, hospital or business) to prevent heat stroke which is a medical emergency.

11. Start and finish runs near bodies of water. Many summer long-run groups start and finish runs at Barton Springs where you can cool off by jumping into the pool. Neighborhood pools are fine too. The most immediate way to cool down after a run is to immerse yourself in water. Feels good too.