Running in Heat and Humidity

It’s summer, the day is beautiful, and you want to take advantage of the blue skies. You step outside and it is oh so hot that you suspect the sun has it out for you. You have not prepared, and begin sweating before taking your first step. Fortunately, there are some ways you can resist the heat. This post will provide an overview of heat-related running recommendations.

Appropriate Clothing

It is unlikely that you will have chosen too many layers to head out into the heat in, but the clothing you wear is crucial. In hot and humid conditions, our bodies lose lots of bodily fluid in sweat, so it would be wise to wear clothing that can handle moisture well. Running apparel made from wick-away materials pulls sweat away from your skin and onto clothing so that it can evaporate, keeping you relatively dry.

Another thing to consider is headgear on runs greater than one hour. My head sweats a lot when I run. Teaching me that when you’re far into a run, your may eyes burn from salty sweat. You can’t use your clothing to remove sweat without putting more into your eyes. My solution was to buy a headband to catch my sweat. It worked like a charm for me, so I would suggest finding something that works for you.

Plan Before Going Out

I found running in the middle of the day to be most difficult. So for my long runs, I often rise before the sun does to get outside. Alternatively, you could wait until the sun sets and some of the heat dissipates. I’ve found this to be an excellent option when waking up early is not practical. While some of the humidity remains in the air, it’s a lot better than having the midday sun beating down on you.

Bring Hydration

When you sweat, you lose water and electrolytes. The longer you sweat, the more depleted your body will become. To stay hydrated, I would recommend bringing water for most circumstances. If running for greater than an hour in the heat, consider also bringing electrolyte-based drinks or gels.

When hydrating, it is important to only take small sips constantly throughout runs rather than guzzling it all down quickly. A rule of thumb is 250-500 mL per hour, but you should strive to replace what is lost in your sweat. You could find yourself cramping up because your body hasn’t been able to allocate the liquids to the best-served areas. Over-hydration is rare but could occur from drinking nothing but water over very long runs. You could find yourself caught up with water poisoning which is potentially life-threatening. You need water and electrolytes for longer runs, because electrolytes like sodium are needed to shuttle water into your cells.

Get Used To The Heat

At first your body may struggle to handle the heat efficiently. The more you put yourself out there (safely of course) the better it will become at adapting to the heat and humidity. It can take up to two weeks or longer for your body to adjust.

Slow Your Pace

Running in the heat is not like running in cool conditions. Heat causes your body to pull more blood to your skin surface, which means there is more work for your heart to do to keep up. Your pace under these conditions will almost certainly be lower, but may feel like full effort. If it is humid, sweat will not evaporate well, possibly resulting in overheating. Your body is constantly trying to regulate it’s temperature, which in turn means you’ll tire out quicker. Run at a slower than normal pace to avoid overheating.

Listen To Your Body

If you’re feeling like the sun or heat is getting to be too much, it probably is. Don’t try to push the last bit of your run to get it over with. Stop. It could be as minor as heat cramps, or as severe as heat exhaustion. Either way could be much worse than the small hit your pride will take from cutting a run short.

Protect Yourself From The Sun

Sun protection should be obvious, since it’s a good idea without exercise. Protecting your skin while running can help keep your body a little cooler. Sunblock, sunglasses, hats, and wick-away clothing with SPF protection can go a long way, especially for long runs in hot and humid temperatures.



An aspirational runner who has been at it since 2013. Eric started this site to help those like him find the information they need to get started.

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