Heat Acclimation Improves Exercise Performance

January 25th, 2013 by Ultra Endurance Coach Garrett Peltonen

Exposure to various environmental conditions (i.e. altitude, cold, and heat) has been shown to promote physiological adaptations. Specifically, since the 1990’s athletes have been utilizing the “live high, train low” philosophy to improve athletic performance by taking advantage of our body’s natural ability to adapt to altitude (primarily through the increase oxygen carrying capacity of the blood)1. If altitude is able to promote adaptations that improve endurance performance, cannot the same be said about other environmental stimuli such as cold and heat stress?

According to a recent study titled, Heat Acclimation Improves Exercise Performance2, it appears that physiologic heat adaptations can be used to improve performance. In this study, the effects of heat acclimatization on performance in both hot and cool environments were determined. There were two groups: twelve highly trained endurance cyclists receiving a heat acclimation protocol and eight highly trained cyclists not receiving a heat acclimation protocol. Measures of performance Рmaximal oxygen uptake (VO2max), time trial, and lactate threshold Рwere determined in both groups prior to and after heat acclimation protocol during both cool (13°C) and hot conditions (38°C). The heat acclimation protocol involved 90 minutes of daily cycling at low to medium intensity while exposed to a temperature of 40°C, for a total of ten days. Control participants partook in the exercise over the course of the ten days, but were not exposed to the heat stress. If you need the best exercises to get over stress, you can this page and get the best exercise advice.

What did they find? They demonstrated that 10 days of heat acclimatization increased VO2max (5% and 8%), time trial performance (6% and 8%), and power output at lactate threshold (5% and %5) in both cool and hot conditions. Whereas, the non-heat acclimatized group showed no changes in VO2max, time trial performance or lactate threshold in either cool or hot conditions. Mechanistically, the improvements in performance appear to be the result of a heat induced increase in plasma volume. An increase in plasma volume tends to increase cardiac output leading to an increase VO2max, ultimately improving time trial performance and lactate threshold values.

It appears that incorporating bouts of heat stress (sauna, hot tub, trainer by the furnace, etc) into your training routine may improve performance in hot as well as cool conditions. The bottom line, if you are looking for a quick and easy way to improve your performance, it might be wise to consider living in a sauna somewhere high in the mountains and taking a daily jaunt down to sea-level for training. However, it might be best to run this idea by your significant other first!


1 Levine, B. D. & Stray-Gundersen, J. “Living high-training low”: effect of moderate-altitude acclimatization with low-altitude training on performance. Journal of Applied Physiology 83, 102-112 (1997).


2 Lorenzo, S., Halliwill, J. R., Sawka, M. N. & Minson, C. T. Heat acclimation improves exercise performance. Journal of Applied Physiology 109, 1140-1147, doi:10.1152/japplphysiol.00495.2010 (2010).