Infrared Sauna and Health, What the Research Says About Heat Exposure

Infrared saunas come with bigger health claims than almost any other piece of wellness equipment. Detox, weight loss, younger skin, a stronger heart. Some of that has research behind it, some has none, and the brochures rarely tell you which is which. What follows is what the studies actually show, where they came from, and how to read them if you are thinking about heat as part of managing a condition.

What Infrared Heat Actually Is

Every warm object gives off infrared radiation. A woodstove does, a radiator does, so does the person sitting next to you. Infrared sauna panels are built to give off a lot of it in a controlled way. The energy crosses the cabin and is absorbed by your skin and the tissue just beneath it, so you warm up while the air around you stays at a modest 45 to 60 degrees Celsius (about 115 to 140 Fahrenheit).

Most of the research has used far infrared, the longer wavelengths that warm the surface of the body. Some newer cabins add near infrared lamps as well. Those are a different technology with their own small research base, mostly on skin and wound healing, and the two should not be lumped together.

In a traditional electric sauna the heater warms a bed of stones and the stones warm the air to 80 to 100 degrees. You feel the heat on your skin first and your core temperature climbs as the air does its work. With infrared the order is reversed. The air feels mild, yet your core temperature still rises over 20 or 30 minutes, your heart rate climbs and you sweat heavily. The body’s response is similar in kind, lower in intensity, and spread over a longer session.

Where the Research Started

Most of what we know about infrared heat and health comes from Japan, and from one group in particular. In the 1990s, cardiologists at Kagoshima University began treating heart failure patients with a 60 degree far infrared sauna for 15 minutes, followed by 30 minutes resting under blankets to hold the warmth in. They called it Waon therapy, from the Japanese for soothing warmth.

A 2002 study in the Journal of the American College of Cardiology01824-1) treated 20 heart failure patients this way every day for two weeks and compared them with 10 similar patients who simply rested in a warm room. Symptoms improved in 17 of the 20 treated patients. The lining of their blood vessels responded better to blood flow, and a blood marker of heart strain fell. The comparison group did not change.

The largest test came in 2016, when 19 Japanese hospitals randomized 149 patients with advanced heart failure to ten days of daily Waon therapy or standard care. The results are in Circulation Journal. The treated group improved in symptom grade and in how far they could walk in six minutes, with no serious adverse events. The heart strain marker moved in the right direction, but that change was not statistically significant. That is a fair summary of infrared heart research as a whole. Real, measurable improvements in how people feel and function, with the harder biological markers lagging behind.

Smaller Studies on Pain, Fatigue and Diabetes

The same Japanese team tried the therapy on other hard to treat conditions. In a chronic pain study, 46 inpatients went through a four week program of rehabilitation and psychological treatment, and 22 of them also had a daily far infrared sauna session. Pain scores fell in both groups. Two years later, 77 percent of the sauna group had returned to work, against 50 percent of the others.

A pilot study in chronic fatigue syndrome gave ten patients Waon therapy five days a week for four weeks. Fatigue scores, mood and day to day functioning had improved by the end, pain had not, and nobody reported side effects. Ten people is a very small study, and the authors said as much.

In Canada, a family doctor in a rural British Columbia village invited his patients with type 2 diabetes to use a far infrared sauna for 20 minutes, three times a week, for three months. Their scores for physical health, general health, social functioning, stress and fatigue all improved, as reported in the Journal of Alternative and Complementary Medicine. Blood sugar control was not what the study measured, so this is a quality of life finding rather than a diabetes treatment finding.

For joints, a Dutch pilot study of 17 people with rheumatoid arthritis and 17 with ankylosing spondylitis found that pain and stiffness eased during infrared sessions, and nobody’s disease flared over the four week program. DiseaseFix looked at that study more closely in its article on saunas for rheumatoid arthritis.

Put together, these studies share a pattern. They are small and most have no placebo group. What they measure is how people feel, and on those terms the results are consistently positive. Whether infrared heat changes the course of any disease is a question none of them was built to answer.

Claims the Evidence Does Not Support

Detox is the big one. Sweat is almost entirely water and salt. Your liver and kidneys remove waste products, and no study has shown that sweating removes a meaningful amount of anything they would not clear anyway. Weight loss claims rest on the same sweat. You will weigh less when you step out of the cabin, and the same as before after your next two glasses of water.

Cholesterol is a more interesting case because it has actually been tested. The review of far infrared research in Canadian Family Physician found consistent evidence against the claim that infrared sessions lower cholesterol, alongside limited but moderate evidence for blood pressure and heart failure. Claims about cancer, immunity and anti aging have no clinical trials behind them at all.

How Infrared Compares With a Traditional Electric Sauna

This matters because most of the headline findings people quote about saunas and long life come from Finland, where the saunas are the hot, dry, traditional kind. The Finnish cohort studies that linked frequent sauna use with lower rates of cardiac death, stroke and dementia followed people who used sauna heaters running at 80 degrees and above, not infrared cabins. The first and best known of them is in JAMA Internal Medicine. A 2018 review in Mayo Clinic Proceedings suggests the benefit works through better blood vessel function, lower arterial stiffness and lower blood pressure. Infrared heat produces the same kind of response at a gentler level, so it is reasonable to expect some of the same effect. Reasonable is not the same as shown.

If you already own an electric sauna, the evidence gives you no reason to switch. If heat at 85 degrees is more than you can tolerate, infrared is the option that lets you stay in long enough to get properly warm, and the clinical research above was done at exactly those lower temperatures.

Safety Points Specific to Infrared

• The air is cooler, but your core is not. Thirty minutes at 55 degrees still raises body temperature and still pulls fluid out of you. Drink before and after, and treat dizziness as a signal to stop.
• Longer sessions mean more chance of dozing off. Falling asleep in any sauna is dangerous. Set a timer and stay upright.
• Sauna heat does not damage pacemakers or defibrillators, but the heart condition behind the device may be the real issue. Ask the cardiologist who looks after it before you start, rather than relying on the cabin maker’s word.
• Blood pressure tablets, diuretics and anything that affects sweating or heart rate change how you respond to heat. Mention the sauna to whoever prescribes them.
• If you are pregnant, the same caution applies as with any sauna. Ask first.
• If your cabin has bright near infrared lamps, do not stare into them. Far infrared panels do not have this issue.
• Panel cabins produce low level electromagnetic fields, as any electrical appliance does. There is no established health effect at those levels, but if it concerns you, ask the maker for its test report before you buy.

Reading the Research Before You Buy

A few things are worth noticing. The clinical protocols were daily, supervised and short. Fifteen minutes at 60 degrees followed by half an hour wrapped in blankets is not how most people use a home cabin, where sessions tend to run 30 to 45 minutes at a lower temperature with no rest period afterwards. Nobody has tested whether the home routine does the same thing.

The quality of infrared sauna heaters varies a great deal, and the research tells you nothing about which brand to buy. What it does tell you is that consistency mattered in every positive study. Three sessions a week for three months, or daily for two weeks, not an occasional half hour when you remember.

So the honest position is this. Infrared heat is safe for most people, it makes people with several chronic conditions feel better in small trials, and it has not yet been shown to change the course of any of them. If that sounds like a modest conclusion, it is. It is also more than most wellness equipment can say.

References

1. Kihara T et al. Repeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failure. Journal of the American College of Cardiology, 2002. https://doi.org/10.1016/s0735-1097(01)01824-1
2. Tei C et al. Waon therapy for managing chronic heart failure, results from a multicenter prospective randomized WAON-CHF study. Circulation Journal, 2016. https://doi.org/10.1253/circj.CJ-16-0051
3. Masuda A et al. The effects of repeated thermal therapy for patients with chronic pain. Psychotherapy and Psychosomatics, 2005. https://doi.org/10.1159/000086319
4. Soejima Y et al. Effects of Waon therapy on chronic fatigue syndrome, a pilot study. Internal Medicine, 2015. https://doi.org/10.2169/internalmedicine.54.3042
5. Beever R. The effects of repeated thermal therapy on quality of life in patients with type II diabetes mellitus. Journal of Alternative and Complementary Medicine, 2010. https://doi.org/10.1089/acm.2009.0358
6. Oosterveld FG et al. Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitis. Clinical Rheumatology, 2009. https://doi.org/10.1007/s10067-008-0977-y
7. Beever R. Far-infrared saunas for treatment of cardiovascular risk factors, summary of published evidence. Canadian Family Physician, 2009. https://pmc.ncbi.nlm.nih.gov/articles/PMC2718593/
8. Laukkanen T et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine, 2015. https://doi.org/10.1001/jamainternmed.2014.8187
9. Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and other health benefits of sauna bathing, a review of the evidence. Mayo Clinic Proceedings, 2018. https://doi.org/10.1016/j.mayocp.2018.04.008
10. Hussain J, Cohen M. Clinical effects of regular dry sauna bathing, a systematic review. Evidence-Based Complementary and Alternative Medicine, 2018. https://doi.org/10.1155/2018/1857413

Written by the team at Northern Lights Cedar Barrel Saunas, a Manitoba company that has built cedar saunas and supplied sauna heaters across North America for more than 25 years.