76. HEAT ACCLIMATION: PREPARE TO PERFORM AT YOUR BEST IN A HOT ENVIRONMENT!

Photo by Markus Spiske on Unsplash

In previous posts we saw that heat exposure can boost physiological adaptations that increase performance not only in a hot environment (>30 °C) but even when exercising at normal temperatures (~15-20 °C). These physiological adaptations are mainly an increase in haemoglobin mass and an increase in mitochondrial capacity which both boost the ability to produce watts through the aerobic system and so raise the first and second lactate/ventilatory thresholds, critical power and FTP. If you want to learn more on this topic you can read more here, here and here.

However, heat exposure to boost performance when exercising at normal temperatures is a new (started only ~5 years ago) research direction of the broader ‘heat exposure’ topic. On the other hand, heat exposure to attenuate the typical decrease in performance that occur when exercising in a hot environment has been investigated in research setting and applied on the field by more than 20 years. According to the different aims, the heat exposure protocols can have some small differences (we will underline them in a later post). So, here at KnowledgeisWatt we think it is essential to make the following terminological distinction:

• Heat Training: heat exposure to boost physiological adaptations that increase performance in all environments, even at normal temperature.

• Heat Acclimation: heat exposure to attenuates the typical decrease in performance that occur when exercising in a hot environment. It can be called also heat acclimatization if it is undertaken in a natural environment (training outside in the hottest hours of the day), while the term acclimation is used when environmental setting are voluntary manipulated (environmental chamber, indoor training while wearing additional clothes, …)

It has been reported that professional road cyclists’ mean maximal power over durations ranging from 5s to 20min are decreased by 2-7% between 30-35 °C and by 9-18% at >35 °C of environmental temperature. So, it is crucial to understand how to attenuate such a performance decrease in a hot environment. In this regard, one widely used and effective solution is using a precooling jacket (learn more here). However, heat acclimation has been recognized as the most important intervention one can adopt to reduce physiological strain and optimize performance during competition in the heat. (1)

To divulgate physiological underpinnings and best practices about heat acclimation strategies, we will refer to a review published by Tyler and Colleagues (University of Roehampton, London, UK) on Sports Medicine in 2016, which put together, reviewed and resume the data of ~100 (!) research papers previously published on the topic.

Have a good read.