Infrared Sauna: What the Research Actually Supports, Session by Session

Most of what gets written about infrared saunas online sits somewhere between a supplement ad and a physiology lecture. It is often hard to tell which claims have research behind them and which have a marketing budget behind them. This article takes the slower path. It explains what an infrared sauna session is, what the published studies looked at, and what those studies do not show.

Start with one fact, because it changes how everything below should be read. Most of the long term sauna research was done in traditional saunas, not infrared ones. Infrared is a newer way to deliver heat to the body. The studies that followed people for years and decades were almost all done in traditional Finnish saunas, and the research on infrared specifically is still being built. Where results exist for each type, they are usually reported separately, so this article keeps them separate too.

What an infrared sauna is

A traditional sauna heats the air, and the hot air heats you. An infrared sauna uses panels that give off infrared energy, which the body absorbs directly. Because of that, the cabin can stay cooler than a traditional room while your skin and core temperature still rise and you still sweat.

Infrared is split by wavelength:

• Far infrared is the longest wavelength and is absorbed at the skin. Most home infrared cabins are mostly or entirely far infrared.
• Near infrared is a shorter wavelength. Some cabins add near infrared panels or a separate light.

When you compare two cabins, the numbers that actually differ are heater type and count, the wavelength each heater gives off, cabin size and wood, voltage, warm up time, and the EMF reading at the bench. EMF, short for electromagnetic field, is the faint electrical field that any heater and its wiring give off. Some buyers want that kept low, and cabins built for it are tested and sold as low EMF. All of these numbers are on each product page, and they are a better basis for a decision than any single claim about results.

What a session looks like

Across the research and common practice, an infrared sauna session usually falls in this range:

• Cabin temperature around 113 to 150°F (45 to 65°C) for a far infrared cabin. That is lower than a traditional sauna at 175 to 210°F (80 to 100°C), because the heating works differently.
• About 20 to 45 minutes, often built up slowly over the first few weeks.
• The observational studies people cite most often tracked sauna use of about 4 to 7 times per week. Lighter use was linked to smaller differences.
• A cool down and water afterward. In a contrast routine, a cold exposure follows.

None of that is a prescription. It is the range the studies and general guidance tend to sit inside.

The cardiovascular research and how to read it

The most cited work comes from a study in eastern Finland that followed about 2,300 middle aged men for roughly two decades. Researchers recorded how often each man used a sauna and tracked what happened to his health over that time.

• Laukkanen T, et al. JAMA Internal Medicine. 2015;175(4):542 to 548. PMID 25705824.
• Laukkanen JA, et al. Age and Ageing. 2017;46(2):245 to 249. PMID 27932366.
• Laukkanen JA, et al. Mayo Clinic Proceedings. 2018;93(8):1111 to 1121. PMID 30077204.

In that group, more frequent sauna use was associated with lower rates of several heart and brain related outcomes over the follow up period. The direction was consistent across the papers, and it held after the authors adjusted for common risk factors.

Here is what that kind of study can and cannot tell you.

It is observational. It shows that a habit and an outcome tend to go together. It is not a controlled trial, so on its own it cannot prove the sauna use caused the difference. People who use a sauna five times a week may differ from people who never do in ways that are hard to measure fully.

It was done in traditional saunas. The temperature, the humidity, and the session length in a Finnish sauna are not the same as a far infrared cabin.

It was one type of person, middle aged Finnish men. The size of any link can be different in other groups.

The exact figures from these papers, the effect sizes and the confidence intervals, are in the protocol guide rather than here. A percentage on its own, with no study design attached, is easy to misread. The guide gives you the number and the context together.

Heat and the idea of adaptation

A common theme in heat research is hormesis, which means a mild, tolerable stress that prompts the body to adapt. Heat shock proteins, a group of molecules involved in handling cellular stress, are one of the mechanisms studied in that context (Kregel KC. Journal of Applied Physiology. 2002;92(5):2177 to 2186. PMID 11960972).

This is an open research area, not a settled result, and it has its own article coming. For now: the mechanism is real and is being studied. Going from "heat activates this pathway" to "you will feel or measure a specific benefit" is the step the research has not finished making.

Heat and sleep

The clearest short term effect tied to heat is about temperature. Raising your core temperature and then letting it fall is associated with falling asleep faster, through the same drop in core temperature the body uses at night (Harding EC, Franks NP, Wisden W. Frontiers in Neuroscience. 2019;13:336. PMID 31105512).

This is why an evening session, finished well before bed so the body has time to cool, is a common choice. It is a link to faster sleep onset through temperature. It is not a treatment for insomnia or any sleep disorder.

Infrared compared with traditional

• Traditional sauna: heats the air to a high temperature, lets you add humidity with water on the rocks, and is the format used in the long term studies above.
• Infrared sauna: heats you with panels at a lower air temperature, usually drier, easier to tolerate for people who find hot rooms hard, and often lower voltage with a shorter warm up on home models.

Neither is better in the abstract. If your goal is to match the conditions of the studies above, that points toward traditional. If comfort and install limits matter more, that often points toward infrared. A separate article works through that choice in detail.

What the research does not establish

Stated plainly so it is not left to implication:

• It does not show that an infrared sauna treats, cures, or prevents any disease or medical condition.
• The strongest long term data is observational and was collected in traditional saunas.
• Claims that a sauna clears "toxins" from the body are not supported by this research in any real clinical sense.
• Infrared saunas are general wellness devices. They are not medical grade equipment and are not a substitute for medical care.

Where to start

If you have read this far, the useful question is not "which sauna" but "where does heat sit for someone starting from where I am." Running heat, cold, and light from day one suits some people. A slower build, light first, then cold, then heat over several weeks, suits others. The right answer depends on your current sleep, recovery, activity level, schedule, and how much experience you already have with heat and cold.

Find My Protocol matches those five answers to one of four starting points and a week by week plan. It takes about two minutes and does not require a purchase.

References

• Laukkanen T, et al. JAMA Internal Medicine. 2015;175(4):542 to 548. PMID 25705824
• Laukkanen JA, et al. Age and Ageing. 2017;46(2):245 to 249. PMID 27932366
• Laukkanen JA, et al. Mayo Clinic Proceedings. 2018;93(8):1111 to 1121. PMID 30077204
• Kregel KC. Journal of Applied Physiology. 2002;92(5):2177 to 2186. PMID 11960972
• Harding EC, Franks NP, Wisden W. Frontiers in Neuroscience. 2019;13:336. PMID 31105512

For the specific effect sizes from these studies, and the full protocol details, see the protocol guide.

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The products sold by Peak Regenerate are not medical devices and are not intended to diagnose, treat, cure, or prevent any disease or medical condition. This article is for educational and informational purposes only. Talk to your physician before starting any heat, cold, or light exposure routine, especially if you have a heart condition, are pregnant, or take prescription medication. Individual results vary. Peak Regenerate does not provide medical services through this platform.