Running In Hot Weather: Everything You Need To Know

Running In Hot Weather: Everything You Need To Know

Real runners run – in rain, hail, sleet, and snow. And they brave running in hot weather too.

This last in particular is no cake-walk. Sure, nothing’s falling towards you from the sky, and that’s surely a plus. But it’s much harder to breathe when it’s hot, and you seem to sweat more, and to weigh more, and it’s generally just uncomfortable.

In some cases, it could even be dangerous.

Of course, if you live in a hot climate – or if you’re about to move to one – you may have no choice. Hell, maybe it’s that time of year for you when the unrelenting cold gives way to the heat. Whatever your issue, you may be wondering how exactly you can do your runs not just safely but effectively. You may be wondering if that’s even possible.

We’ve got you covered.

Is It Bad To Run In Hot Weather?

Yes, if you do it wrong.

No, if you do it right.

If you’re not used to the heat, you’ll notice the difference almost immediately. In addition to obviously sweating more (and thus becoming dehydrated at a much quicker rate (as well as losing electrolytes at a much higher rate)), the heat will also make you feel worse.

First off, dehydration will cause what’s referred to as a “cardiac drift” – that is, the more dehydrated you get, the harder your heart as to work to keep up with your level of exertion.

And mentally, you’ll feel like you’re exerting much more than you would in cooler weather. That’s because your core temperature rises the hotter it is; this causes your innate “rate of perceived exertion” to increase, which in turn causes you to slow down to maintain your core temperature.

You might think that you, in the interest of fulfilling your running goals, should probably ignore the messages your body’s sending you. Just push through it, you might tell yourself.

Don’t do that.

Below is  a list of what can happen if you’re not careful (as well as what you can do to counter each of these things):

  • Dehydration. This one is one we’ve already mentioned and a no-brainer. The more you sweat, the more fluids you lose, the more dehydrated you become. If you lose more than four percent of fluids during your run, you’re likely to experience a host of issues, including fatigue, dizziness, and cognitive disorientation. To prevent all of this unpleasantness from occurring, make sure that you’re properly hydrated before you start your run. And how do you know when you’re hydrated? Just check the color of your urine: if it’s clear, you’re good to go. If it’s dark, drink up. Check out our article on hydration for runners for more information.
  • Cramps. This one is also related, in part, to how much you sweat. Remember, when you sweat, you not only lose fluids, but electrolytes too. A shortage of electrolytes causes muscle spasms that can occur both during your run as well as hours after it. Check out our articles on calf cramps and side cramps to mitigate this issue.
  • Heat Exhaustion. Again, pretty obvious. If you’re dehydrated and your core temperature rises above 104 degrees Fahrenheit, then you’re in trouble. If you ever feel this is happening to you, STOP RUNNING, and find a cool place to have a cool drink and kick up your feet and relax. Not every battle can be won.
  • Heatstroke. This one is so serious that you’ll absolutely need a medical professional if this happens to you. It occurs when your core temperature exceeds 105 degrees Fahrenheit. Cognitive disorientation and confusion, lack of balance, clumsiness, and even a lack of sweating are all signs of heatstroke. Again, a medical professional will have to counteract such dangerously high body temperatures. Don’t take this one lightly: it can be fatal.

The Benefits of Running in Hot Weather

Oh yes – despite all the depressingly negative stuff above, there are plenty of (scientifically-backed) benefits of running in the heat.

For one, it can, paradoxically, actually lower your overall core temperature. Think Vegeta training at 300 times normal gravity. After a while doing that, he didn’t even feel it when he unexpectedly found himself standing in Pui Pui’s planet at 10 times normal gravity. The result? An easy victory for Vegeta.

It’s kind of like that.

Once you acclimate properly to the rigors of hot climate training, less harsh climates will feel and indeed be, well, a lot less harsh.

This is all backed by research: training in the heat for sustained periods, in a smart, effective way leads to increased blood plasma volume, as well as increased skeletal muscle force, both of which will make you a better runner. In addition, research shows that heat acclimation training can actually give you more benefits than even altitude training.

Oh, and it also increases your rate of perspiration. Now, we’ve discussed the downsides of this – dehydration, loss of electrolytes, cramping, fatigue, etc. But there’s a good side too: perspiration cools your body down. And as long as you’re properly re-hydrating, your cooler body should be able to handle longer, more intense runs than it would have otherwise.

Some research even shows that constantly running in hot weather even increases the rate at which your muscles receive oxygen.

In short, if you do it safely, there are a ton of benefits to be reaped.

Final Tips

  • Drink lots of water before and after your run. Make sure you also drink during your run if you’re running long distances.
  • Take it easy. This doesn’t mean slack off – but it does mean you should listen to your body. Don’t try too hard to maintain a specific pace. If you’re starting to feel sluggish or woozy, or like something’s wrong, there’s no shame in slowing down and taking your bearings. Remember, the heat is hard on your body (for reasons we’ve discussed above), so you need to give it time to acclimate. This is especially true if you’re brand new to the climate.
  • Try to run during the morning hours. Mornings are generally much cooler, and therefore easier on the body.
  • Opt for trail running rather than running on asphalt or concrete. The latter two actually bounce heat back onto you, which doesn’t help anyone.
  • Protect your skin with sunscreen. Age spots are no joke. Melanoma is even less funny.
  • Wear light colors if you’re going to be under the sun. What you wear matters in the sun. Dark colors will absorb heat; light colors won’t. Avoid cotton as well.
  • Wear the proper gear. Preferably gear that is moisture-wicking, light, and breathable. Our thin running socks, for example, are perfect for hot weather.
  • Lastly: keep a positive attitude. Some research suggests that running in high temperatures is harder simply because people think it’s harder! There’s something to be said here for positive thinking – if you think you can, you’re probably right.

And that’s all there is to it. All you need to know about running in hot weather.

If you have any questions or concerns, be sure to leave a comment below.


  1. Outside