Infrared saunas are increasingly marketed as a post-exercise recovery tool that can reduce pain and fatigue, but the scientific evidence supporting these claims remains limited and conflicting.

So do infrared saunas cause physiological changes that accelerate recovery, or do they simply reduce the feeling of aching muscles?

Traditional Finnish saunas heat the surrounding air to between approximately 70°C and 100°C. In contrast, infrared saunas use panels that emit infrared radiation to heat the body more directly, allowing them to operate at a lower air temperature between 40°C to 60°C. Both methods heat the body, but deliver the heat differently.

Infrared saunas should not be confused with photobiomodulation, sometimes called red-light therapy. That technique uses controlled doses of red or near-infrared light to produce biological effects without substantially heating tissue. Its clinical applications are still being investigated and are not fully standardised. An infrared sauna primarily provides whole-body heat.

Why heat might aid recovery

Heat exposure widens blood vessels in the skin and activates heat-shock proteins and other cellular pathways involved in stress protection and tissue repair. These effects provide a plausible reason for studying heat as a recovery strategy.

However, physiological plausibility does not necessarily translate into meaningful improvements in recovery. Most studies have not measured intramuscular temperature, making it difficult to determine whether the target muscles were heated enough to produce the proposed effects.

Heat has also been claimed to support recovery by increasing blood flow and........

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