Performance
Athletes use sauna for more than relaxation. Passive heat exposure can act like a training stimulus. It challenges thermoregulation, expands plasma volume in some protocols, and may support heat acclimation. At the same time, the research is mixed depending on the sport, the timing, and the heat method.
This page summarises what the evidence suggests and how to interpret it responsibly.
Why heat can support performance
Heat exposure can drive adaptation
Repeated heat exposure can promote physiological adaptations linked to heat acclimation, including changes in plasma volume and thermoregulatory efficiency. These adaptations can translate into improved endurance performance in some scenarios.
Endurance: what the classic sauna study found
Post-exercise sauna may improve endurance running performance
A widely cited study of competitive male runners reported that adding post-exercise sauna bathing for 3 weeks produced a meaningful improvement in endurance performance. The authors linked the improvement primarily to increased blood and plasma volume.
This is one of the strongest specific data points supporting sauna as a performance tool, but it is not universal across all populations and protocols.
Recovery: what systematic reviews say
Evidence is not definitive for acute recovery benefits
A 2025 systematic review assessing post-exercise heat exposure concluded that the current evidence is not strong enough to draw definitive conclusions about recovery and training-induced performance adaptations. Some immediate improvements have been observed in certain contexts, but study quality and outcomes vary.
The best interpretation is that heat exposure can be a useful tool, but it is not guaranteed to improve recovery for everyone.
Heat acclimation methods and alternatives
Sauna is one of several passive heating strategies
Heat acclimation protocols also include hot-water immersion and other passive heating approaches. Research comparing different methods suggests they can produce meaningful thermal adaptations, with some methods potentially producing larger adaptations than others depending on protocol design.
Strength and hypertrophy: emerging but early
There is ongoing interest in whether passive heating can support strength training outcomes. Newer studies explore adding sauna programs alongside resistance training and measuring strength and body composition changes. This area is promising but still emerging, and results depend heavily on training status and program design.
Practical guidance for athletes
When athletes often use sauna
- After endurance sessions as a heat acclimation add-on
- On low intensity days for relaxation and parasympathetic recovery
- In controlled blocks leading into hot-weather races
What matters most
- Hydration and electrolyte replacement
- Session duration and temperature
- Timing relative to training intensity
- Individual tolerance and cardiovascular safety
The performance trade-off most people ignore
Sauna is systemic. Heat is not evenly distributed.
For men, prolonged heat can elevate scrotal temperature. That is a separate, localized stress that is not required for performance adaptation.
KRYO WEAR is designed to help you keep the systemic benefits of sauna while reducing unnecessary localized overheating by creating a targeted cooling microclimate where male biology is most temperature sensitive.
Sources
- Scoon GSM, et al. Effect of post-exercise sauna bathing on the endurance performance of competitive male runners (Journal of Science and Medicine in Sport, 2007).
https://pubmed.ncbi.nlm.nih.gov/16877041/ - Ahokas EK, et al. Effects of Post-Exercise Heat Exposure on Acute Recovery and Training-Induced Performance Adaptations: A Systematic Review (2025, open access).
https://pmc.ncbi.nlm.nih.gov/articles/PMC12488549/ - McIntyre RD, et al. Comparison of heat acclimation by post-exercise hot water immersion vs conventional heat acclimation (2021).
https://www.sciencedirect.com/science/article/pii/S144024402100133X - Bartolome I, et al. Four-week passive extreme heat sauna program alongside resistance training (Applied Sciences, 2025).
https://www.mdpi.com/2076-3417/15/19/10762 - Overview review: health and fitness benefits attributed to sauna exposure (2025).
https://nsuworks.nova.edu/cgi/viewcontent.cgi?article=2899&context=ijahsp