michael harr, mba
tips for running in the heat and humidity
I H-A-T-E running in the heat and humidity. Can't. Stand. It! That said, I've learned just about every trick in the book to try to beat the heat, profuse sweating, and general misery that is summer running. What follows is the quick rundown.
like many things, beating heat and humidity is a matter of smart planning, preparation, and execution

safety first

Heat warnings. If there is a heat warning in effect, it's a good idea to take your run indoors to the dreadmill. Short of that, try to time your run during a cooler part of the day, dial down your pace, take walk breaks, and generally do what you need to avoid overheating.

Heat exhaustion. When you run in the heat, you run the risk of experiencing heat exhaustion. Symptoms include confusion, dark colored urine, dizziness, fainting, fatigue, headache, cramps, nausea, vomiting, diarrhea, pale skin, profuse sweating, and/or rapid heartbeat. If any of these symptoms appear, you may have heat exhaustion, and you should try to cool off immediately.

Heat stroke. Pushing beyond heat exhaustion, you may wind up having a heat stroke. Symptoms include a high body temperature (>104), altered mental state or behavior, nausea, vomiting, flushed skin, rapid breathing (even after slowing down or walking), racing heart rate, and/or throbbing headache. Should this be the case, cool off immediately and seek medical attention.

Route and contact information. As always, be sure to inform someone of your route and check-in time, and carry your ID, list of medical conditions, and emergency contact info on your person (I use Road ID to make this easier)

time of day

Early morning. Far and away, the best time to run is in the early morning when temperatures are more moderate. If you can get out just as darkness begins to lift, all the better.

Late evening. If you can't make your run happen in the morning, try late in the evening. Timing the end of your run to coincide with dusk will keep you out of the worst of the heat.

Night. For anyone who really hate the heat, night running can be a match made in heaven. While it's not always practical to run late into the night and get up for work the next day, it's great to mix in a long night run over the weekend.
maximize shaded routes by running them in the early morning or late evening when shadows are longest


Shaded sidewalks and trails. It's easy to find routes that have plenty of shade if you take the time to find them. I routinely train at our local arboretum where the trees give some relief to the summer heat.

Water fountains. One of the fastest ways to short circuit your summer run and possibly land yourself in the emergency room is to run out of water. Find a route that has plenty of water fountains to refill you water bottles and remember you'll need to drink 8-12 oz. per mile to stay hydrated.

Shorter loops or out and backs. To keep you in the shade and hydrated, plan routes that may be shorter loops or out and backs. By shortening routes to keep you shaded and near drinking water, you won't have that, "oh shit!" moment when you're baking in the sun and suddenly out of water.
nothing will short circuit a hot, humid run faster than dehydration - drink 8-12 ounces per mile


Wicking everything. Running in anything but lightweight, wicking fabrics is crazy. That goes for underwear too! Everything you put on your body should wick moisture away from your body so you can stay cool and avoid overheating.

Light colored clothing. Black absorbs more light which means more heat with means more arduous running. Wear light colored clothing that reflect more light, keeping you cooler and more comfortable.

Hydration belt or pack. Some runners can get by with a handheld bottle. Most, however, need to carry more water - especially if running longer distances. Be sure to bring a hydration belt or pack that is easily refilled. I prefer a belt with bottles; I call it my Invincibility Belt:-)

Ice bottles. No matter what distance you plan to run, pack some ice in your bottles. The ice keeps your water cooler longer and can help you beat the heat by cooling you from the inside out. Run long enough or in hot enough weather and you may want a water bottle that starts as a block of ice.

Drop bags. For very long runs or for runs where water fountains aren't available, you can leave a drop bag with extra water bottles. This is standard procedure at most ultramarathons, and you can do the same. Always bring far more water than you think you might need.
give yourself permission to walk; allow your body cool down at the first sign of overheating


Expectations. You will run slower in the heat and humidity. Take that fact to heart, let it marinade in your mind, and adjust your pace expectations. How much? Most runners will pace anywhere from 30 seconds to 2 minutes per mile slower in extreme heat. On the plus side, however, when the heat subsides, you'll score a slew of new PR's.

Hydrate first. Before you start your warm-up, drink at least 10 ounces of water first. In fact, doubling that isn't a terrible idea. When you start well hydrated, your body will be better able to cool itself during your run. Starting even slightly dehydrated is a bad idea and potentially dangerous.

Run by effort, not pace. Turn off your running app's audio cues or set them for longer intervals because you need to run by effort, not pace. The clock is fine on race day or when you're targeting a PR, but those situations are relatively few and far between over the summer. Focus on effort and listen to your body.

Hydrate often. A good rule of thumb is to drink 8 to 12 ounces of water for each mile that you run. I've averaged closer to 12 ounces per mile over the summer and generally slow down for a drink every half mile or so. Going too long without water is bad. Don't go there.

Permission to walk. Regardless of how seasoned you are as a runner, never be afraid to walk when needed. If you feel like you might be overheating, you probably are - slow down and walk, if needed.
it may take an hour or more to fully cool down from a hot run - take your time and let your body recover

after your run

Cool down. While it may be tempting to head quickly to an air conditioned car or home, don't neglect your cool down. Walk for a bit, stretch, do what you do to cool down. And, drink more water while you're at it.

Blast the AC. Once you've finished your cool down, crank up the air conditioning, and help your body cool itself. There are few things better than sitting in from of a car vent, feeling the cool air hit your skin, and enjoying your post run afterglow.

Turn up the fan. It takes a little longer to cool down after running in the heat. If you don't have a fan, consider getting one because when you sit down to change, it feels AWESOME!

Take a cool shower. To finish up and return to normal society, a cool shower is ideal. Notice that I didn't type 'cold' shower - a cool shower is all you need.