It’s that time of year when hot weather begins to drastically change your experience on the bike. Targets easily nailed while riding in mild 65-degree weather feel completely different at 95. While the body is masterful at regulating skin blood flow and sweat rate to control your core temperature [1], high heat environments present an immense challenge to the endurance athlete.

Prioritizing Survival

Current research [2] points toward there being a “central governor” or on-off switch in your brain that seems to limit your exercise performance when your core temperature climbs toward 40º C [3] . The end result is less power to the pedals as your body prioritizes survival over a silly power target on your Garmin.

The first step in training with a power meter in high heat situations is to understand the impact heat will have on your power output. Don’t beat yourself up because you’re unable to complete a workout based off of power targets designed with cooler temperatures in mind. Expect at least a 10% reduction in your power production when the heat begins to rise.

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Understanding The Impact

Acknowledging the impact of heat on your exercise performance will insure you get the most out of your available training time while enabling you to progress toward your season objectives. Here are three simple modifications to make when the heat begins to rise…

  1. Wake up early to execute your workout in the morning hours before the temperature rises. Plan ahead by looking at the weather forecast for the upcoming week. Get to bed early the day before to accommodate a shift in your training schedule
  2. Plan to reduce the intensity of your workout all together if you decide to train in the heat. While you won’t be able to train at the same intensity you would by riding earlier in the morning, take comfort in knowing that your body will undergo unique training adaptations by exercising in the heat [4].
  3. Focus on your hydration long before you head out to exercise in the heat. Hyperhydration has been shown to improve performance [5] and can be an important component in staving off dehydration when you’re sweating buckets.


1. Wendt, D., L.J. van Loon, and W.D. Lichtenbelt, Thermoregulation during exercise in the heat: strategies for maintaining health and performance. Sports Med, 2007. 37(8): p. 669-82.
2. Gonzalez-Alonso, J., C.G. Crandall, and J.M. Johnson, The cardiovascular challenge of exercising in the heat. J Physiol, 2008. 586(1): p. 45-53.
3. Benzinger, T.H., Heat regulation: homeostasis of central temperature in man. Physiol Rev, 1969. 49(4): p. 671-759.
4. Lorenzo, S., et al., Heat acclimation improves exercise performance. Journal of Applied Physiology, 2010. 109(4): p. 1140-1147.
5. Goulet, E.D.B., et al., Pre-Exercise Hyperhydration Delays Dehydration and Improves Endurance Capacity during 2 h of Cycling in a Temperate Climate. Journal of Physiological Anthropology, 2008. 27(5): p. 263-271.