Infrared Sauna Research

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This is a compilation of heat therapy research I’ve come across in my quest to experience the various health benefits from infrared sauna use, and learn different strategies to implement therapeutic hyperthermia successfully. I am not a doctor, this is not medical advice. I add my own personal synopsis comparing personal experiences to the research summary in each sub section. Please note that my personal experience synopsis alongside is not medical or science backed research, only the cited sources and quotations. However, my hope is that the everyday average peer in need of this information most to improve their own health, will gain more knowledge and benefit from a layman’s description coinciding with the medical research.

** Most apparent contraindications for any sauna use (steam or infrared, or any heat therapy): do not sauna while pregnant, or have existing cardiovascular disease. Please see your doctor to discuss medical conditions. 

What Is A Far Infrared Sauna & It’s Medical Applications

FIR saunas

“In these cabins, the heating elements are typically heated to about 300– 400° C and the emission is in the FIR range, that is, the heat exchange between the body and the environment is almost purely radiative (radiant heating) with cabin air temperature being at around 40°C or less (Figure 4). Heating of the skin with FIR warming cabins is faster (in comparison with the conventional saunas) but higher irradiance of the skin must be applied in order to produce noticeable sweating. These cabins are frequently used in Japan where the practice is called “Waon therapy” []. Waon therapy has been used extensively in Japan [] and Korea [] for cardiovascular conditions and diseases, particularly chronic heart failure [] and peripheral arterial disease []. FIR sauna therapy has been used to improve cardiac and vascular function and reduce oxidative stress in patients with chronic heart failure []. Beever [] asked whether FIR saunas could have a beneficial effect on quality of life in those patients with type II diabetes. The study consisted of 20 min, three times weekly infrared sauna sessions, over a period of 3 months. Physical health, general health, social functioning indices, and visual analogue scales (VAS) measurements for stress and fatigue all improved in the treatment group. A study of patients with rheumatoid arthritis and ankylosing spondylitis showed a reduction in pain, stiffness, and fatigue during infrared sauna therapy [].”  Src:

“For FIR used as a therapeutic modality the alternative terms “biogenetic radiation” and “biogenetic rays” have been coined and widely used in the popular literature. FIR wavelength is too long to be perceived by the eyes, however, the body experiences its energy as a gentle radiant heat which can penetrate up to 1.5 inches (almost 4 cm) beneath the skin. FIR energy is sufficient to exert rotational and vibrational modes of motion in bonds forming the molecules (including the water molecules) as well as resonate with cellular frequencies. Resulting epidermal temperature is higher when the skin is irradiated with FIR than if similar thermal loads from shorter wavelengths are used. The prolonged erythermal response due to FIR exposure has been proposed to be due to increased epidermal temperatures associated with it, but levels of FIR that do not produce any detectable skin heating can also have biological effects.”

Mayo Clinic Sauna Bathing Health Benefits

“Sauna bathing, an activity used for the purposes of pleasure, wellness, and relaxation, is linked to a remarkable array of health benefits. It is a safe activity and can even be used in people with stable CVD, provided it is used sensibly for an appropriate period of time. Plentiful putative mechanistic pathways underlying these associations have been proposed, but many of these are not well understood. Further research work in the form of well-designed intervention studies is crucially needed to understand the pathophysiological mechanisms that underlie the associations between sauna bathing and its health benefits and to establish any causal relevance to the associations and whether these could be translated into clinical benefits. Sauna bathing may be a remedy to the call for additional lifestyle interventions needed to enhance health and wellness, particularly in populations that have difficulty exercising, and also as an adjunct to exercise.” Src:

The Effects Of Far Infrared Therapy On Chronic Health Conditions

“As a potential complementary therapy, FIR radiation had both thermal and non-thermal effects. The thermal effect of FIR therapy could increase blood flow and vasodilation by heating the tissue (hyperthermia), similar to ordinary thermal therapy composed of heat pads or hot water. In addition, FIR treatment with low levels of delivered energy (non-thermal effect) also had biological activities., A study of patients receiving HD treatment had shown decreases in stress and fatigue levels by FIR stimulation rather than thermal treatment (heat pads), which was probably attributed to the non-thermal effect. An explanation of non-thermal effect of such low energy levels was that nanoscopic water layers got disturbed by low irradiances, leading to the change of cellular membrane structure, then made the therapeutic effects.” Src:

Does Heat Therapy Really Exponentiate The Detoxification of Toxins

Mobilization Of Fat Soluble Xenobiotics,


Src: PubMed Crinnion W

Auto-Immune, Toxicant Induced Chronic Health Problems

Far Infrared VS Radiant Heat

“Existing evidence supports the use of saunas as a component of depuration (purification or cleansing) protocols for environmentally-induced illness. While far-infrared saunas have been used in many cardiovascular studies, all studies applying sauna for depuration have utilized saunas with radiant heating units. Overall, regular sauna therapy (either radiant heat or far-infrared units) appears to be safe and offers multiple health benefits to regular users.”

Src: PubMed 

Does Sauna Temperature Matter For Detox & Health Benefits?

Many people have argued for years about the ideal temperature to use for sauna benefits. Some claim you cannot elicit heat shock proteins under 170 degrees, however I find it interesting that several different practitioners, were able to enhance detoxification with a wide variety of temperature ranges.

This coincides with my own personal experience, which is the act of hyperthermic therapy, no matter the temperature, is beneficial in several ways. (even in short duration)


“Heat settings varied. The Crinnion protocol used lower temperatures (120-130°F), Rea protocol used moderate temperatures (140-160°F), and the Hubbard Purifcation. Rundown used the highest temperature range (140-180°F). “There is currently insuficient evidence to determine an optimal temperature for depuration. Despite the differences in temperature settings, as well as the other components of these depuration protocols, the published studies report health benefits.”


Far Infrared Therapy For Treating Chronic Disease, Heart Failure, & Hypertension

“Furthermore, FIR rays have been applied in treating various chronic diseases, such as hypertension, heart failure, and vascular endothelial dysfunction, which are associated with the depletion of tetrahydrobiopterin (BH4), a critical cofactor for NO synthases., FIR therapy improves blood flow in heated surface areas, causing an increase in vascular shear stress and enhancement of the activity of GTP cyclohydrolase I, which benefits BH4 synthesis., Thus, the increased availability of BH4 may provide key insight into the underlying mechanisms of sauna therapy. A recent study demonstrated that capillaries control blood flow primarily related to active pericyte relaxation. In addition, pericyte death in rigor results in a permanent decrease in blood flow in capillaries and damages neurons after stroke. These mechanisms resemble FIR in improving capillary dilation and blood flow and may reflect the promotion of stroke recovery by FIR stimulation. In other words, FIR therapy may alleviate stroke by inhibiting pericyte death.”


Dry VS Wet Sauna: Heat Stress Core Temp Comparison

Summary: rectal core temperatures increase very closely in both wet and dry saunas.

I found it very interesting the difference in cabin temperature cited here, although rectal temperature was within a reasonable range in both cases.  Of course they’re recommending that anything approaching hyperthermic states can potentially be hazardous, the data is interesting nonetheless.


Waon Therapy For Treating Chronic Fatigue Syndrome


Whole Body Hyperthermia Reduces Depression In Random Clinical Trial

Src: PubMed

Rheumatoid Arthritis


Chronic Pain




Stress Reduction


Chronic Heart Failure & Arrhythmia


The Health Benefits of Sauna Bathing
Saunas have been used by cultures throughout the world for the purposes of cleansing and healing, including the American Indians, Russians, Koreans, and most famously, the Finnish people. In fact, the very word “sauna” comes from Finnish, and refers to an unornamented room paneled with spruce or pine, with wooden benches made of spruce, obeche, or aspen. The bulk of research on the health benefits of sauna have, in fact, been conducted in Finland, though there are many other sauna practices distinguished by length of use, heat source, and relative humidity.

Physiological Effects of Heat
Sauna heating generates mild hyperthermia in the body — raising its core temperature — in such a way that the cardiovascular, neuroendocrine, and cytoprotective systems all work in concert to restore the core temperature and recondition the body’s endurance to heat. Exposure to high temperature stresses the body, provoking a rapid and robust reaction. First the skin heats to 40°C (104°F). Then the body’s core temperature rises slowly from 37°C (98.6°F, or normal) to 38°C (100.4°F), then more rapidly to 39°C (102.2°F). Cardiac output may increase 60%-70%, though the heart rate remains largely unchanged. 50% to 70% of the body’s blood flow moves from the core to the skin, stimulating 0.5 kg worth of sweat. The plasma content in the blood rises.

This entire set of physiological responses leads to hormesis, or the acclimation of the body to stress as a result of repeated exposure to a mild stressor. Hormesis not only acclimates the body to future instances of stress, it repairs cell damage as well. Moderately vigorous exercise promotes roughly the same effect, and sauna use has often been proposed by medical professionals as an alternative exercise for patients who are unable to do so. The hormetic effects of heat stress limit protein damage and activate the body’s antioxidant, repair, and degradation processes. Similar processes are stimulated by exercise.

Heat shock proteins (HSPs), transcription factors such as Nrf2, FOXO3, IL-6 and IL-10, and pro- and anti-inflammatory responses are mechanisms triggered by heat all the body’s cells at the molecular level, and play a pivotal role in such functions as immune response, cell signalling, and cell-cycle regulation.

HSPs, for instance, are a family of proteins that exist at a certain constant level in all cells, playing a huge role in protein assembly, folding, export, turn-over, and regulation. However, as a result of normal metabolism and immune reaction, they can become damaged, leading to complications such as neurodegenerative diseases like Parkinson’s and Huntington’s. Heat stress, however, can robustly stimulate the production of HSPs, leading to increased levels of up to 49%. These increased levels of HSPs were, in turn, implicated in augmented cellular heat repair and increased metabolic rates of up to 28%.

Nrf2 and and IL-10 are anti-inflammatory factors, whereas IL-6 is pro-inflammatory. The body’s health requires the right balance of inflammation and anti-inflammation to counteract stress. Interestingly, heat exposure can benefit the production of all of them. For instance, heat exposure activates Nrf2, which in turn stimulates the production of an HSP called heme oxygenase-1 (HO-1), which in turn inhibits the production of certain pro-inflammatory molecules associated with heart disease. The stimulation of IL-6, which is vital for homeostasis and immune response, in turn stimulates the production of the anti-inflammatory IL-10. This is commonly observed after vigorous exercise, and after exposure to sauna.

FOXO3 plays a central role in easing the body’s natural aging process by repairing damage to DNA, proteins, and lipids, restoring the loss of stem cells, and increasing the production of genes that also play a pivotal role in these and other activities. In response to heat stress, FOXO3 proteins form a complex with sirtuin 1, or SIRT1, which shifts FOX03’s activities away from cell death and toward stress resistance.

Health Benefits
Studies conducted over the past several decades demonstrate that sauna produces numerous salubrious effects for the health. One study in particular, the Kuopio Ischemic Heart Disease Risk Factor (KIHD) study, showed strong correlation between sauna use and health and longevity among a cohort of 2300 middle-aged men exposed to sauna temperatures of at least 78.9°C (174°F) for at least 20 minutes.

Cardiovascular disease is one of the most widespread health problems in the world, leading to 18 million deaths — and a great deal of the tragedy is that so many of them are preventable through lifestyle changes, including sauna use. The KIHD investigation showed that those who used the sauna two to three times per week suffered a 27% lower rate of fatal cardiovascular disease than those who didn’t. Men who used the sauna twice as often suffered 50% fewer cardiovascular-related deaths. In fact, participants suffered 40% less premature mortality in general, regardless of underlying cause. These findings held true regardless of age, lifestyle factors, and activity levels. Further benefits included 66% lower risk of dementia and a 65% lower risk of Alzheimer’s disease, as well as a 77% lower likelihood of developing psychosis, regardless of factors such as age, socioeconomic status, and so forth.

The effects of sauna on heart and blood pressure are particularly well understood. Sauna use, again, has effects similar to those of moderate exercise, ultimately lowering normal blood pressure and increasing heart rate. In fact, studies have shown that sauna is useful for treating congestive heart failure, ischemic heart disease, left ventricular function, and more. But heart health is only one of the major benefits of sauna use. Other studies have tied sauna use to reduction in inflammation and depression, as well as enhanced neurogenesis and attention span. There is further evidence that sauna heat can promote growth hormone, and insulin and glucose regulation.

Inflammation is another area in which sauna has proven benefits. Although a crucial part of the body’s immune response system, it can cause numerous deleterious effects. Acute inflammation can cause swelling, irritation, and fever after minor injury or illness. Chronic inflammation occurs at the cellular level and is often asymptomatic, though it plays a huge role in such major illnesses as cancer, cardiovascular disease, and diabetes. Sauna use, however, can lead to lower resting levels of C-reactive protein (CRP) and higher levels of anti-inflammatory agents, such as the IL-10 listed above.

There is other medical evidence that sauna use can boost physical endurance and athletic performance. For instance, one study showed that one 30-minute post-workout sauna session twice a week for three weeks could increase runners’ endurance by 32%, their plasma volumes by 7.1%, and their red blood cell count by 3.5%. It can augment athletes’ acclimation to increased body temperatures, and reduce muscle atrophy by up to 37%. It has been shown that sauna use boosts blood flow to the skeletal muscles and enables the body to maintain a longer sweat rate. Sweating caused by sauna is also tied to the reduction of such harmful toxins as heavy metals, BPA, and to a lesser extent PCBs and phthalates.

Risk Factors
Like exercise and like medical therapies, sauna carries risk factors and potential side effects. First, some good news! Sauna has been shown to be relatively safe for pregnant women, though pregnant women with toxemia are at risk for reduced blood flow to the fetus. It has been shown to be safe for children over the age of two under adult supervision.

Now, the definite don’ts. Those suffering acute illness accompanied by fever or inflammatory skin conditions should not use saunas. Anyone taking any kind of medication, whether prescription or over the counter, should consult a physician before using the sauna, as should those suffering a cardiovascular condition. As discussed previously, there is substantial evidence that sauna use is beneficial for those suffering heart conditions, but the particular effects will vary case-by-case.

There is also some danger of electrolyte loss through exposure to sauna heat. Though the average person loses 0.5 kg of sweat in a sauna session, some lose substantially more. This can lead to a loss of electrolytes, particularly sodium, chloride, potassium, magnesium, and calcium. Dehydration from overexposure to heat can lead to fatigue and skeletal muscle cramps. Anyone using the sauna should take care to sufficiently hydrate before and after, and to consume electrolyte-rich foods such as seeds, nuts, spinach, avocado, and fish. Sauna use has also been shown to reduce sperm counts and motility in men who use saunas, though the effect is reversible within a few months of ceasing sauna use.

Sauna use has been shown to have enormous health benefits, from the improvement of cardiovascular condition to fertility, mental health, and more. It relaxes muscles and stimulates blood flow to skeletal muscle, leads to greater excretion of toxins through sweat, and stimulates molecules within the body’s cells that not only strengthen the body’s response to heat stress, but reduce inflammation, aging, and the development of tumors. It is generally healthy for adults of all ages, as well as for children and special medical populations with appropriate supervision.

Additional Resources:

DIY Sauna Course

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