Summary
Mike Matthews takes a skeptical, evidence-based look at infrared sauna claims by reviewing 23 scientific studies. He explains how infrared saunas use infrared light to heat the body rather than steam or hot air, and methodically evaluates common marketing claims against the actual research. He finds that while marketers dramatically overstate benefits, there is legitimate evidence supporting several uses. The episode concludes that there is good evidence infrared saunas can reduce joint pain and stiffness in rheumatoid arthritis, decrease oxidative stress, and improve mood and symptoms of depression. There is weaker but promising evidence for cardiovascular benefits including improved blood vessel flexibility and lower blood pressure, as well as potential improvements in chronic fatigue symptoms. Matthews debunks claims about weight loss (saunas cause water loss, not fat loss), detoxification (no fat burning means no meaningful toxin release), skin health (pores don't meaningfully change size with temperature), and cancer prevention (no evidence whatsoever). He recommends far infrared saunas in the 6-20 micrometer wavelength range and suggests sessions of 25-30 minutes at least every other day.
Key Points
- Good evidence that infrared saunas reduce joint pain and stiffness in rheumatoid arthritis, with effects persisting after sauna use stopped
- Infrared saunas can decrease oxidative stress in the body, which may be associated with reduced risk of heart disease
- Studies show improved blood vessel flexibility and lower blood pressure, though mechanisms aren't fully understood
- Infrared sauna improved mood and reduced anxiety and depression in chronic fatigue syndrome patients, with improvements increasing over time
- Weight loss claims are false: saunas cause water loss through sweat, not fat burning or increased metabolic rate
- Detoxification claims are overstated: without triggering fat burning, saunas cannot meaningfully release toxins stored in fat cells
- No evidence supports claims about cancer prevention, immune system boosting, or skin health improvement from infrared saunas
- Far infrared rays (6-20 micrometers) are the most beneficial wavelength; recommended sessions of 25-30 minutes at least every other day
Key Moments
Infrared sauna reduces joint pain and stiffness in rheumatoid arthritis
Mike reviews studies showing infrared sauna can reduce joint pain and stiffness in people with rheumatoid arthritis. One study ran just four weeks with subjects spending only an hour per week in the sauna, yet improvements persisted even after sauna use stopped, suggesting anti-inflammatory effects.
"studies do indeed show that infrared sauna can reduce joint pain and stiffness in people with rheumatoid arthritis. The effects that we've seen so far are minor, but definitely promising"
Evidence for cardiovascular benefits including improved blood vessel flexibility
Research shows infrared saunas may improve blood vessel flexibility and lower blood pressure, potentially through increased nitric oxide production. Rigid blood vessels are a hallmark of cardiovascular disease, so anything that increases flexibility is beneficial for long-term heart health.
"research shows that it may indeed improve your blood vessels ability to expand and to adapt to changes in your blood pressure. And this is important because rigid blood vessels are a hallmark of cardiovascular disease."
Weight loss and detox claims debunked by the evidence
Mike explains that saunas cause water loss, not fat loss, and do not increase metabolic rate. Without triggering fat burning, infrared saunas cannot meaningfully release toxins stored in fat cells, despite marketing claims about detoxification.
"saunas just make you hot and sweaty, and research has shown this does not burn calories or even indicate that you are burning more calories than usual. It just means that your internal temperature is getting too high and your body needs to cool down."
Infrared sauna improves mood and may reduce depression and anxiety
Studies found infrared saunas improved mood and reduced anxiety and depression in chronic fatigue syndrome patients, possibly through reduced oxidative stress. Improvements occurred after sessions and increased over time, suggesting effects go beyond placebo.
"the improvements that were seen didn't occur during the sauna sessions, but after, and they actually increased over time, which does suggest that they were less likely due to the placebo effect."
