Ultrarunning: Best Practices for Heat and Humidity

January 17, 2012

This article is part of Endurance Planet’s ultrarunning article series. If you have questions, comments or feedback about “Best Practices for Heat and Humidity”, please leave it below in the comments section…

If you’ll be joining an ultramarathon that will be held in a hot and humid environment, then you must realize that you’ll need more than just strength, endurance, and resolve to finish the race. You’ll also need to be fully equipped with the tested knowledge of those who’ve done it and lived to tell about it to help you survive the extra challenges which this particular climactic condition will present. Here’s an outline of some best practices relating to this particular challenge.

Acclimatize ahead

Acclimatizing to heat two weeks before the race is highly recommended. This can be achieved by performing the training routines in environments with ambient temperatures similar to those of where the ultra will be held. Acclimatized athletes are better at dissipating heat thus are more capable of regulating their core body temperatures.

Recover fully

Full recovery in between the heat training sessions is crucial. Bear in mind that the heat acclimatization phase should be done a couple of weeks prior to the race, which is also the time for tapering. So avoid overtraining and burnout by closely monitoring your heart rate. Exercise in the heat but make sure your training heart rate is not much higher than what you normally would have when training in moderate climactic conditions. And allow yourself to fully rest in between these sessions as well.

Hydrate sufficiently

Dehydration must be avoided as it can significantly compromise one’s performance under hot and humid conditions. So hydrate adequately and smartly. Drink plenty but in properly spaced and controlled portions. And opt for specially formulated beverages which contain polymeric sugars and extra salt as these are easily absorbed by the body and provide more nourishment to allow faster cellular recovery.

Load up on carbo

Glycogen utilization is higher when performing in hot and humid conditions. So make sure that you include large amounts of carbohydrates in both your food and beverages to make up for this high glycogen burning rate.

Avoid high altitudes

You would want to keep away from high altitude places especially when you’re in the acclimatization phase. For one, staying in high altitude places of 2,000 meters or above automatically causes the blood to thicken as it’s the body’s mechanism of coping with lower oxygen in the air. And when your blood viscosity is higher, you’ll be more prone to dehydration. High altitudes typically have lower ambient temperatures too and can cause your body to lose the adaptation to heat that you’ve already built up.

Fly ahead

You may want to fly to the race venue a couple of days prior to the race itself. For one, you’ll have the extra time to get accustomed to the climate you’ll be racing in. You’ll be better rested as well. Plus, air in the plane is dry and pressurized. So if you fly just a few hours before the race, your body will surely be dehydrated from the cabin air.

Don appropriate attire  

Think twice about wearing tight fitting and dark colored clothes for the race. As you probably already know, these types of clothing tend to absorb more heat and can inhibit your body’s heat dissipating capacity. Opt for light colored, preferably white, and loose race attire instead.

Some things to avoid

Aspirin in high doses causes an increase in body temperature so high performance athletes are advised against its intake both during the acclimatization phase and the race itself. Beverages such as coffee and beer have diuretic properties so it should be avoided immediately prior to and after the ultra.


Do you have questions about coping with heat and humidity, or what you’ve read so far? Do you have any ultrarunning pointers of your own to add? Please leave your feedback, comments and questions below, and we promise we’ll respond.

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