Running outside on a summer day in the American Midwest means dealing with the heat. Even waking up early to run or waiting until evening doesn’t offer much of a relief, although it does spare me from the blazing summer sun.
All winter long I look forward to the summer weather. Longer days mean no runs in the dark. Warmer temperatures mean I don’t have to bundle up just to find myself overheating a mile into my run and shedding my jacket, gloves, or hat. Summer is my favorite time of year. Yet, as cold as Chicago gets in the winter, summers here can be brutal.
My runs feel sluggish and slow in hot weather and I start to wonder if there’s any benefit to my slogging around my neighborhood streets. Would I be better off having a faster and more comfortable run (although admittedly more boring) inside on the treadmill? Or should I brave the elements and run outside?
For one thing, there is something deeply satisfying about finishing a run in difficult conditions. And in addition to that, hot weather running has some great benefits for overall fitness.
It’s as good as high altitude training
There are advantages to running in hot summer weather. Researchers have found that becoming acclimated to the heat changes your body in the following ways:
- Reduces overall core temperature
- Increases sweat rate
- Increases blood plasma volume
- Reduces blood lactate
- Increases skeletal muscle force
This all combines to mean that training in hot and humid conditions strengthens your heart by stressing your cardiovascular system. Your blood flows to your skin which causes reduced blood flow to your muscles. This causes your overall blood volume to increase to compensate.
Running in the heat creates training conditions that are similar to training in higher altitudes. There’s a reason the flagship US Olympic Training Center is located in Colorado Springs. Research has shown, high-altitude training improves athletic performance. And running outside on a hot summer day has a similar effect.
It increases your VO2 max
VO2 max is the maximum amount of oxygen that your body can use during intense exercise. Although the most accurate test for VO2 max will come from an exercise lab, non-professional athletes can still get an estimate of theirs. Many health clubs will perform a VO2 test for you. You can also figure it out for yourself using an online tool or a fitness tracker.
The higher the rate, the more your muscles can process oxygenated blood. You’ll be more fit, running will feel easier, and you’ll be able to sustain your run for longer. You can improve your VO2 max with interval and tempo runs. And, with running in hot conditions.
In 2010, a University of Oregon professor researched the effect of heat training on athletes. After exercising in 100-degree heat for ten days, participants’ time trials and power output and lactate thresholds were up 5 to 6%. Plasma volume was also up, but for the control group that trained in 55-degree weather, nothing had changed.
There are dangers to training in hot weather
These benefits come with acclimated training in hot conditions. Note the word, acclimated. It takes time to build up and in the short term, there are dangers to running in the heat. It’s very important you listen to your body and don’t push yourself too hard when the temperatures first begin to rise.
Add humid conditions to the heat and there’s even more stress on your body. Humidity makes it harder for your body to cool itself as the sweat doesn’t evaporate easily from your skin.
Watch for these warning signs for heat exhaustion and don’t try to run through it if it happens to you.
- Feeling faint
- Muscle cramps
- Chilled skin with goosebumps (despite the heat)
If you ignore the signs of heat exhaustion, it can lead to a heat stroke. This is much more serious and occurs when your body temperature rises above 104 degrees. Your skin feels hot to the touch, and you may either stop sweating or sweat heavily. You may feel disoriented, with a racing heart. A heat stroke requires immediate medical care as it can lead to organ failure and even death.
How to stay safe
Ease yourself into summer running and listen to your body. You need time to train yourself to handle the heat. Don’t expect to go out and run at your usual pace and distance the first hot day. Experts say it takes seven to ten days for your body to acclimate to hot weather.
You can follow these tips to safely acclimate to hot weather running:
- Hydrate. You may need to substitute water for a sports drink to get your electrolytes replenished.
- Dress appropriately. Wear light colors that are breathable and lightweight.
- Check the temperature first. Know what you’re up against. If your area has excessive heat warnings, it may be a good day to skip your outdoor run, go shorter, or start earlier in the day to avoid the hottest part of the day.
- Listen to your body. This is always important. Don’t force yourself to run through unsafe conditions.
When the weather cools
If you’ve trained all summer in the heat, you’re going to feel a great relief on that first, cool fall day. Your body will have changed, your legs will be light, and you’ll feel like you are flying.
Yes, I did say summer is my favorite time of year. But thinking of a fast run in the refreshingly brisk weather of a sunny fall day, I find myself reconsidering.
Jennifer Geer writes about running, health, and wellness. Follow her on Twitter.