sweaty runner

Tips for Running in the Summer Heat

If you’re a runner, you know that the first thing you check before heading out for a run is the weather. Is it raining? Is it hot? What’s the humidity? And if you’re a seasoned runner, you skip right to checking the dew point. Dew point is the temperature at which the air is saturated – meaning the temperature at which the air has 100% humidity. 

Dew point is a good way of gauging how comfortable the air will be, which is obviously important for runners. A high dew point means a high saturation of water in the air, which sucks for running.

Heat + exertion + high water vapor content in the air = a perfect storm of your body not being able to cool down efficiently:

  • The air itself is hot, so there is no external cooling effect from the air.
  • Your body responds by trying harder to sweat, pulling blood circulation to the surface (away from your GI tract – more on this later).
  • Sweat can’t evaporate off your skin (the air is already largely saturated, remember), so it stays put, and your body temperature stays high.
  • Your heart now has to work harder & your lungs go into overdrive to try to get oxygen to your system. (More blood is being diverted to these processes – again away from the GI tract and also your working muscles.)

And suddenly your 5-mile run feels like mile 12 of a half marathon. It’s not because you’re suddenly less fit or less capable. It’s that physiologically, these runs are very different from your 50-degree, 40% humidity, mid-March runs.

exercise, fitness, jogging

It’s super important to take precautions and plan for these runs. You can’t always fully anticipate the weather, but do your best to check the forecast and time your run accordingly. Be sure to manage your expectations! Don’t try to  set a 5k PR at noon on a 90 degree day.


The following tips can help make your summer runs more comfortable & sustainable:

  1. Adjust your running schedule. If you’re a morning runner but mornings are extra humid right now, you might need to switch some runs to late afternoon or evening (or vice versa). The point is, adjust your running to the conditions – don’t force a run that is doomed to fail from the start.

  2. Pay attention to how you feel. Hot weather runs aren’t runs that should be dictated by your Garmin. As your body temperature rises and you’re unable to cool down properly, your brain also gets hotter. This means clouded judgment. We runners tend to be married to the run we planned for, rather than the run we are in. Your hot weather runs need to be dictated by what your body is telling you, not what your brain wants.

  3. Be flexible with your fueling strategy. Remember how we said that your body will divert blood from your GI tract? This means that gel that normally works just fine now may not sit so well. You’re more likely to experience nausea & other GI distress as fuel sits in your stomach longer before being absorbed. You’ll need to experiment with different fueling options to find something that you can tolerate better. Often real-food alternatives (like pretzels or dried fruit) are tolerated better than gels & chews during high-heat runs.

  4. Reduce duration & intensity. This one is kind of a no-brainer, but it bears writing down: when it’s hot & humid and the dew point is high, it’s time to swap that planned 6-mile tempo session for a casual 3-4 mile run. This isn’t the time to worry about loosing fitness (you’ll still be training hard, as your exertion level will be much higher at a much lower output).

  5. Make hydration a priority. I cannot emphasize this one enough. Hydration is always the most important part of a successful run, but when increased heat & body temp factor in, don’t mess around with your hydration levels. If you missed my week of hydration posts on Instagram, go back and read those, or click here to read the last blog post on it. If you want to learn more about hydration & electrolytes for your run, click here.

  6. When all else fails, move inside. Sometimes the best choice is to put ego aside and move that run to the treadmill in a nice air conditioned room (or even a garage with a fan set up).

There’s no reason to fall off the running wagon over the summer, and with a little bit of planning and adaptation, your sluggish summer season will set you up for running gains in the fall. #covid19 has any race plans up in the air at this point, but even if you can’t sign up for an in-person fall event, consider some virtual races to keep yourself motivated to train (with adjustments using the tips above) through the dog days of summer.

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