Now that we’re entering that portion of the calendar that our governor terms “bad heat” we all need to run with a bit more caution. There is no question that the worst weather Austin runners face is in the next three months. Summer doesn’t officially begin for another three weeks, but the last week or so has reminded us what summer running is like. That dynamic duo of extreme heat and high humidity can bring on overheating on a run of just about any length which can lead to heat stroke or exhaustion.
Overheating is really quite simple. When the body can’t cool itself adequately, it just overheats. The reason why 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 like crazy. That’s good. As we sweat, the body sends more blood to the skin where it is then cooled by coming into contact with the relatively cooler air. But while running, our working muscles are also demanding oxygen 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 demands of whatever your running pace is. But running fast obviously takes more work and you begin 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.
Any way you slice it, running in our brutal summer heat is tough stuff. The normally high morning humidity short circuits the cooling/evaporative process. Even though the blood works its way to the skin and we sweat (again, a good thing), the brutal humidity doesn’t allow the sweat to evaporate very well which would cool us down. Running in hot, dryer weather (such as noon) also sucks, but at least it isn’t as humid.
Dehydration is also more pronounced in hot, humid weather. When you dehydrate, you are 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.
Drinking doesn’t actually cool you down, but staying properly hydrated allows you to sweat better which cools you.
Here are some hints for surviving Austin’s heat and humidity:
- Run early or run late (before sunrise or after sunset). The humidity is higher in the morning, but temps are cooler. The sun isn’t as strong and the air quality is also better in the morning as the traffic is lighter.
- If you must run at lunchtime and temperatures are dangerously hot (triple digits), run inside on a treadmill. Or go to Barton Springs for a swim.
- Slow down. The heat slows everyone. Don’t try to ignore the heat by thinking you can run your normal long-run distance or pace. You can’t.
- The less you wear, the better. (The more exposed skin surface, the better the evaporative process—cooling–works.)
- Wear light colored, lightweight shorts, socks and shirts. Don’t wear cotton shirts or heavy socks.
- Drink at every opportunity. Stop at every water cooler on the Butler Trail. 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.)
- Try to run in some areas where there’s shade and near the water. (Hint: the Butler/Lady Bird Lake Trail is ideal. Or start and finish your runs at Barton Springs.)
- 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 running slower on grass, but the grass will be cooler than the sizzling pavement or track.
- Start runs slowly. Your body heats up gradually. By starting a run with an aggressive pace, you’ll simply heat up quicker and eventually pay the price sooner.
- Recognize signs of overheating. Such warning signs as profuse sweating, a light head, nausea, vomiting, fainting are all indications of heat exhaustion. If symptoms occur, stop running. Immediate treatment should be cool drinks, ice application or jump in a pool or lake. If a body of water isn’t available, get the victim into a cool place (such as a store, home, building or business) to prevent heat stroke which is a medical emergency