How to use heat exposure for performance gains

As part of our Biohacking Masterclass Series, we will explore a number of different techniques and practices to improve your daily performance. This series will range from obvious subjects like exercise and nutrition to fringe subjects like breathing techniques and sleep hygiene. Consult your physician before implementing any of these topics. We are not your physician. 


Targeted heat exposure, also called ‘hyperthermic conditioning’ and ‘hyperthermia’, refers to the process of subjecting your body to periods of high temperatures. Raising your core body temperature leads to a host of physiological changes all across your body. Many of these changes are integrally related to mental and physical performance. With improved access to dry saunas, gaining these performance benefits has never been easier. In this article, we’re going to break down the scientific support behind hyperthermic conditioning, including the changes in growth hormone (up to 1600% higher), anabolic/hypertrophic stimulation, and increases in endurance. We will leave you with an understanding of optimal sauna/cooling routines. 

Growth Hormone After Sauna Bathing 

Growth hormone is an anabolic hormone that supports growth of muscle and bone mass. For athletes, optimizing your growth hormone production will promote greater results after your strength and conditioning training.  We’ve talked about how you can increase your growth hormone production through ‘professional’ sleep hygiene, but hyperthermic conditioning has been shown to dramatically increase the amount of circulating growth hormone in a matter of days. 

In studies that subjected participants to Finnish-style sauna bathing, where individuals alternate between heating and cooling, growth hormone levels jumped between 200% and 500%. In a more extreme study design, participants spent two one hour cycles in a 176 ℉ sauna every day for 7 days. By day three, growth hormone levels were 1600% higher than baseline. By day 7, growth hormone had dipped but remained over 300% higher than baseline. 

Growth hormone releasing hormone, which (as you might infer) stimulates the release of growth hormone, increased 400% after a 15 minute sauna at approximately 161 ℉. 

Increased Endurance 

In competitive runners, sauna sessions have been shown to improve time to exhaustion by over 32%. In this study, participants followed endurance training with 30 minute sauna sessions at 195 ℉. Plasma volume increased over 7% over the three week sauna period. 

Hypertrophic Stimulation

For athletes who train for strength and increased lean body mass, saunas have proved to be an excellent hypertrophic (growth) stimulus. Beyond the increase in growth hormone production we spoke about above, hyperthermic conditioning induces the activation of a group of proteins called heat shock proteins (HSPs). Heat shock proteins are excellent mediators of protein degradation and synthesis. In order to promote muscle growth, the ‘metabolic scales’ need to tip in favor of protein synthesis. The induction of heat shock proteins enables this shift by slowing down degradation processes. 

Animal studies (aka ‘in vivo’ studies) have shown hyperthermic stimuli can prevent catabolic (destructive metabolism) states even when muscle groups are immobilized or unused. If you’re faced with an injury from training or competition, finding a way to get in the sauna may help you maintain that hard-earned muscle mass (bonus: how to increase work capacity without increasing muscle damage). 

How can you implement hyperthermic conditioning in your routine? 

Start by speaking with your physician to understand your specific health risks. Don’t sauna alone or after drinking. 

If you have access to a dry sauna, Finnish-style sauna bathing has a rich history (back to 7000BC), strong safety profile (if practiced correctly), and proven performance benefits. If you’re new to hyperthermic conditioning, start with two 15 minute sessions separated by a 20- to 30-minute cooling period. If you’re more experienced, consider more cycles or slightly longer sessions. In our referenced studies, temperatures typically range from 165-200 ℉. 


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