Sauna is the practice of sweating in a small confined wooden room, with temperatures set around 160–194ºF (71–90ºC) for a traditional sauna, 100–150ºF (38–65.5ºC) for an infrared sauna, or 90–120ºF (32– 49ºC) for a steam sauna.

It’s a relaxation technique, a sore-muscle soother, a social activity, and—as science tells us—a beneficial practice for overall health and wellness. Here’s what we know.

Sauna may help reduce blood sugar

Researchers have found that blood sugar values significantly decreased in individuals after only seven 15-minute sauna sessions.[1] Another study found that several far-infrared sauna sessions significantly reduced the blood sugar levels of the participants.[2]

Similar findings were discovered with hot tubs, where the blood sugar levels decreased from an average of 10.1 mmol/L to 8.8. mmol/L after three weeks of regular hot tub use.[3] Animal models have also shown that heat therapy can seriously reduce blood sugar values and increase insulin sensitivity.[4]

Additional health benefits of sauna

Sauna has many potential health benefits, including metabolic health improvements and other benefits to improve general well-being:

• Improved cardiovascular health
• Lowered inflammation
• Improved cognitive function
• Improved mental health
• Improved endurance and muscle mass retention
• Improved detoxification

Regular sauna use has been shown to reduce the risk of cardiovascular-related disease and premature death, while also reducing the risk of developing dementia, Alzheimer’s disease, and psychotic disorder.[5]

Aside from feeling good, what does heat actually do for our bodies? 

How heat therapy promotes wellness from a cellular level

Researchers suggest that heat therapy has these effects due to heat shock proteins, Nrf2, FOX03, Interleukin-6, and Interleukin-10.[5]

Heat shock proteins live inside of all of your cells, and have a very important role related to repairing other proteins inside of the cell. When cells experience stress, the proteins inside can get damaged. Damaged proteins are a real issue for your health, and are related to cardiovascular diseases and conditions such as Alzheimer’s, Parkinson’s, and Huntington’s disease.[5]

Because these heat shock proteins are very important in stopping damage and in repairing other damaged proteins, your cells are so clever that they start increasing the production of heat shock proteins whenever they feel stressed. This process is called the heat shock response.[5]

And even though a sauna might feel relaxing for you, your cells feel the exact opposite—the heat stress causes your cells to seriously increase their heat shock protein levels. Research shows that heat stress causes healthy individuals to produce more heat shock proteins, and that these increased levels stay even as time passes. These increased amounts then contribute to improved cell health and protein repair. [5]

A little more about the science behind heat therapy

The heat from the sauna doesn’t only act directly on heat shock proteins—it also activates a transcription factor called Nrf2. Nrf2 affects several genes of the cells and increases the production of a heat shock protein which in turn breaks down pro-oxidants (you guessed it, the less desired evil twin of antioxidants) and creates antioxidants and anti-inflammatory gas. Through this series of events, Nrf2 protects the cell against oxidative stress and chronic inflammation. And as we discussed in our earlier blog post, chronic inflammation is a major risk in developing chronic diseases related to your cardiovascular system, blood sugar, and gut. [6]

FOX03 proteins (Forkhead box 03) take part in keeping your cells youthful and healthy, while also contributing to functions like tumor suppression, DNA repair, and immune function. The heat stress from the sauna makes FOX03 join with its friend SIRT1: an important player in reducing cell aging. When combined, FOX03 becomes much more resistant to oxidative stress and can do an even better job within the cell. [5]

Lastly, heat stress affects two chemical messengers called Interleukin 6 and 10. After heat stress, the amount of Interleukin-6 in your body increases, which in turn triggers the release of Interleukin-10. Interleukin-10 has strong anti-inflammatory properties and could help reduce chronic inflammation.[5,7]

References

1. V. Shiralkar et al., “Effect of Steam Sauna Bath on Fasting Blood Glucose Level in Healthy Adults”, 2018. Published in Indian Journal of Medical Biochemistry. URL: https://www.researchgate.net/publication/326203347_Effect_of_Steam_Sauna_Bath_on_Fasting_Blood_Glucose_Level_in_Healthy_Adults
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2. M. Imamura et al., “Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors”, 2001. Published in Journal of the American College of Cardiology. URL: https://www.sciencedirect.com/science/article/pii/S073510970101467X?via%3Dihub
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3. P. Hooper, “Hot-Tub Therapy for Type 2 Diabetes Mellitus”, 1999. Published in The New England Journal of Medicine. URL: https://pdfs.semanticscholar.org/010c/f8f018b3cc25363a09d9710640739262e2a7.pdf
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4. S. Kokura et al., “Whole body hyperthermia improves obesity-induced insulin resistance in diabetic mice”, 2006. Published in International Journal of Hyperthermia. URL: https://www.tandfonline.com/doi/full/10.1080/02656730601176824
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5. Found My Fitness, “Sauna", 2020. Published through Found My Fitness. URL: https://www.foundmyfitness.com/topics/sauna#bibid-977555c9e3a108962599f02b5d986dc6
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6. S. Vomund et al., “Nrf2, the Master Regulator of Anti-Oxidative Responses”, 2017. Published in International Journal of Molecular Sciences. URL: https://www.mdpi.com/1422-0067/18/12/2772
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7. C. Raison, “419. Inflammation in Treatment Resistant Depression: Challenges and Opportunities”, 2017. Published in Biological Psychiatry. URL: https://www.biologicalpsychiatryjournal.com/article/S0006-3223(17)31025-9/fulltext

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