Temps for the Haile Gebrselassie Marathon this October will probably in the 60s to 70s. Not bad for running. But training for the Haile Marathon will take several long runs and plenty of shorter easier runs—and most of them will be in the heat of late spring and summer.
If marathoning is new to you, it may come as a surprise that running in the heat of summer is much more difficult than in cooler weather. There’s no question that the summer dynamic duo of extreme heat and high humidity can also bring on overheating on any run of any length which can lead to heat stroke or 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 body’s internal furnace heats up and we sweat. 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 skin. 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. This is very dangerous.
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. The blood and oxygen goes to your working muscles to keep up with the demands of your running pace, but 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 summer heat is tough stuff. Making it worse is if you live where there is high humidity which short circuits the cooling and evaporative process. Even though the blood works its way to the skin and we sweat (again, a good thing), high humidity doesn’t allow the sweat to evaporate very well and thus, cool us down. Running in hot, dry weather might be hard, but it isn’t as hard 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. As you sweat, you lose water and other electrolytes. If you can’t sweat adequately, you’re in big trouble.
Drinking water doesn’t actually cool you down, but staying properly hydrated allows you to sweat better, which does cool you.
Here are some hints for surviving summer’s heat and humidity:
- Run early or run late (before sunrise or after sunset). The humidity is higher in the morning, but temps are obviously lower. The air quality is also better in the morning as the traffic is lighter.
- If you must run at lunchtime and temperatures are extremely hot, run inside on a treadmill. Or go for a very short run. Better yet, go for a swim.
- Slow down. The heat slows everyone down. Don’t try to ignore the heat by thinking you can run your normal long-run distance or pace. You can’t. At least not for very long.
- The less you wear, the better. The more exposed skin surface, the better the evaporating process works.
- Wear light colored, lightweight shorts and shirts. Don’t wear cotton shirts or heavy socks. Never wear sweat pants.
- Drink at every opportunity. 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 areas near the water and/or where there is shade.
- If you need to do a speed workout, consider running at least part of it on a grass field. You’ll be running slower on grass, but will be cooler.
- 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.
- Recognize signs of overheating. Such warning signs as profuse sweating, lightheadness, 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, lake or ocean. If a body of water isn’t available, get into a cool place (such as a store, home, building or business) to prevent heat stroke.