Running Hot

Sweat pouring down your face, stinging your eyes. The heat from the ground blasting back up at you and the lack of a breeze making the air feel like thick soup. You run on, wondering how long you’ll be able to keep this up before something starts to go wrong.

You’ve heard so many stories of runners overheating while running on hot days, but you seem to be coping ok… Right…?


Summer is almost upon us here in my part of the world and warmer weather and clear skies are just too enticing to not run in. But what about the risks of running in the heat?

If you’ve been around running for a while, you would no doubt know a few people that seem to be able to cope with the heat better than others. You’d most likely also know if you are someone who can manage it well or not too.

There are a number of factors that can contribute to you being able to comfortably run in the heat, such as:

1) Acclimatisation – Exposing yourself to a warmer climate for a period of time allows your body to make minor adjustments to how it regulates heat and protects itself from damage. It takes approximately 2 weeks to properly adjust to warmer temperatures, but this can vary from person to person. Keep this mind when you sign up for your first summer race.

The Badwater Ultra Marathon, which is a 135 mile race along a road in Death Valley (United States) and arguably the hottest place in the world, is run at the height of their summer. This race is about as extreme as it gets when it comes to running in heat. Runners have been known to run along the white line to stop the soles of their shoes from literally melting under them. Participants in this race regularly spend time in Death Valley prior to the race, just hanging out in the heat to prepare themselves physically and mentally for it. Some even put a treadmill in a sauna so they can practice running in the heat for months beforehand.

2) Hydration – The amount of liquid you need to take on when running will vary depending on the temperature but also depending on your body type and ability to process those liquids. A general rule to follow for a racing situation in comfortable weather would be about 650ml per hour for the average person. Some of that liquid should be electrolytes and the further you run it may also need to include some energy (calories) if you aren’t able to consume enough in the form of food. A liquid energy source is often tolerated and consumed much more easily anyway.

If you are running in the heat, you may need to as much as double that amount of liquid while running, but the exact formula for you is difficult to know without trialing.

Some general rules to follow are to monitor your urine output and colour. You should be peeing fairly regularly on longer distance runs and the colour should remain clear to pale yellow. If you don’t feel the need to urinate during a longer run, there is every chance you are already dehydrated and getting close to being in trouble. If you are urinating but the colour is dark yellow, orange or in some cases much darker, your kidneys are not processing your wastes properly, your body is becoming toxic an you are at real risk of serious illness.

A good friend of mine had his kidney’s stop functioning while running the Western States 100mile race in California and shortly after the race he found himself in hospital for about two weeks with acute kidney failure. He had broken down so much muscle tissue by pounding through the canyons in the heat of the day that his blood was literally too thick to filter the protein out and he was at a very real risk of dying.

So, drink. Drink often, Drink before you get thirsty and when you run longer than an hour in the heat, include some electrolytes. When you run longer than two hours in the heat, include electrolytes and an energy source.

3) Pace – The runners that I coach would know that my preferred method of training is effort and time based rather than speed/pace and distance. The reason I do this is to help them learn to listen to their body and run at an effort that matches what their body is capable in that moment. This becomes particularly important when running in the heat. If your fastest sustainable pace on your best day is ?km per hour, and on your long runs you like to hold a pace of 60% of your fastest sustainable pace (for example) then there is a tendency to continually check your gps watch to make sure you stay on that pace. This is all good and well, but what if your body is fighting off a cold, or you are tired from having a poor night’s sleep, or you road/trail you are running on has more incline than you normally run on, or there is a head wind…? etc etc…

All these factors have an impact on your energy consumption needs and also on your body’s ability cope with the demands you are putting on it.

If however, you stick to running at a particular effort for a particular time, it allows you to control your output based on how you feel and not on what your watch is telling you to do.

Doing this effectively and still getting maximum benefit from your training takes practice and also requires you to be honest with yourself. It is easy to “just cruise” because it is easy, but if you can check in with your body regularly and push yourself to an effort that is hard but sustainable, you will get the best result with the least risk of injury or illness.

4) Clothing – Wearing the right clothing when running in the heat can make a huge difference. It is all about getting the balance right between enough coverage to prevent over exposure to the sun and little enough that you can dissipate the heat effectively. Technical running clothes are typically sweat wicking which means they draw moisture away from the skin which helps to avoid chaffing and also keeps you cool. Investing in good quality running gear is always worthwhile.

If running in weather that can be unpredictable, wearing a couple of layers is often a good idea, so that you can remove items as needed to help manage your heat.

The main thing is that it is comfortable and dries quickly. Ask any runner for their recommendations and you’ll get inundated with advice.

5) The Mental Game – Running in the heat can be just as much of a struggle mentally as it can physically. If you can relax and accept the heat and then go about doing what you can do to manage it, the mental toll of the heat can be dramatically reduced.

Countless times I’ve seen people “losing it” in the heat during a long run or a race, simply because it has broken them down mentally. There can be a number of reasons why some people do better in the heat than others, but through repeated exposure to exercise in higher temperatures, like anything else, it becomes easier to deal with. The key of course is stay calm, if your body starts to give signs of distress then simply scale back your effort as much as needed, adjust clothing, fluid intake, etc. until you feel back in control.

Please keep in mind that this article does not address the management of Heat Stress, Heat Exhaustion, etc. These are very real and potentially very dangerous.

Personally, I love running in the heat. Providing I’m well prepared for it, the heat just adds another layer of “interesting” to the experience.


Run long,

Shaun Brewster.

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