What infrared saunas do, and what evidence supports that
Infrared saunas use light wavelengths (usually far-infrared, in the 4–14 micrometer range) to heat your skin and underlying tissue directly, rather than heating the air around you the way a traditional sauna does. The heat penetrates roughly 1.5 inches below the skin surface, raising your core body temperature and triggering a sweat response. The mechanism is real and measurable—your skin temperature rises, you sweat, and your heart rate increases, much as it does in a conventional sauna.
What remains uncertain is whether infrared saunas produce health outcomes that differ meaningfully from traditional saunas or other forms of heat exposure. Most claims about infrared saunas—that they detoxify, boost immunity, or treat chronic pain—rest on small studies, animal research, or theoretical mechanisms rather than large human trials. The research that does exist shows infrared saunas can raise heart rate and core temperature, but translating that into lasting health benefit requires evidence that hasn't yet accumulated at the scale needed to make confident claims.
Key Takeaways
- Infrared saunas heat tissue directly through light wavelengths rather than by warming the air, and this mechanism does raise skin and core temperature measurably.
- Most health claims about infrared saunas—detoxification, pain relief, improved circulation—come from small studies or animal research, not large human trials.
- Heart rate and blood pressure changes during infrared sauna use are similar to those in traditional saunas, and the long-term health significance of these changes is not yet established.
- People with heart conditions, uncontrolled blood pressure, or heat sensitivity should consult a doctor before using an infrared sauna, as the cardiovascular stress is real even if the lasting benefit is unclear.
How infrared heat penetrates skin differently than air heat
A traditional sauna heats the air to 160–200°F, and your skin absorbs that heat passively. An infrared sauna keeps the air cooler (usually 120–150°F) but emits infrared light that your skin absorbs directly. That light energy converts to heat in the tissue itself, which is why infrared sauna users often report feeling warm faster and finding the experience more tolerable than a traditional sauna at the same core temperature.
Thermal imaging and skin temperature studies confirm that infrared wavelengths do penetrate deeper than surface heat alone. A 2012 study in the Journal of the American Medical Association found that far-infrared sauna use raised core body temperature and increased heart rate in ways consistent with moderate aerobic exercise. However, the depth of penetration—roughly 1.5 inches—means the heat reaches muscle and subcutaneous tissue but not organs or deep structures. This distinction matters because many claims about infrared saunas assume the heat reaches areas it does not.
Cardiovascular effects during and after infrared sauna use
During an infrared sauna session, your heart rate typically rises to 100–150 beats per minute, and blood vessels dilate to increase blood flow to the skin for cooling. Blood pressure may rise during the session and then drop afterward. These responses are consistent with what happens in a traditional sauna or during moderate exercise, and they reflect real physiological stress on the cardiovascular system.
A 2015 review in the Canadian Journal of Cardiology found that regular sauna use (traditional or infrared) was associated with lower blood pressure and reduced cardiovascular mortality in observational studies. However, these studies tracked people who chose to use saunas regularly, so they cannot prove the sauna caused the benefit—people who use saunas may also exercise more, manage stress better, or have other health habits that drive the outcome. The cardiovascular stress during sauna use is genuine, but whether repeated sessions produce lasting benefit remains an open question, and the evidence does not yet distinguish infrared from traditional saunas.
Detoxification claims and what sweat actually contains
A common claim is that infrared saunas "detoxify" by drawing heavy metals, pesticides, or other toxins out through sweat. This claim rests on a misunderstanding of how the body eliminates waste. Your kidneys and liver filter toxins from the blood; sweat is produced by sweat glands to cool your skin and contains mostly water, salt, and small amounts of metabolic byproducts. Toxins do not accumulate in sweat waiting to be released.
A 2011 study that measured heavy metals in sweat found only trace amounts, and the researchers concluded that sweat is not a significant route of heavy metal excretion. If your body needs to eliminate a toxin, it does so through urine or feces, not sweat. Infrared saunas may make you sweat more than you would sitting in a cool room, but the sweat itself is not a detoxification mechanism. Any feeling of cleansing or renewed energy after a sauna session is likely due to relaxation, improved circulation during the session, or the ritual itself rather than toxin removal.
Pain relief and muscle recovery: what small studies suggest
Several small studies have found that infrared sauna use reduced pain in people with rheumatoid arthritis, fibromyalgia, or muscle soreness. A 2008 trial published in Clinical Rheumatology assigned 62 people with rheumatoid arthritis to either infrared sauna sessions or a control group and found pain scores improved more in the sauna group over four weeks. However, the study was small, did not use a sham sauna control (so placebo effects cannot be ruled out), and did not track whether the benefit lasted after the study ended.
The mechanism proposed is that increased blood flow and heat reduce muscle tension and inflammation. Heat does produce temporary pain relief—that is why heating pads work—but whether infrared saunas produce longer-lasting benefit than other heat sources (a hot bath, a heating pad, or a traditional sauna) is not established. Most studies comparing infrared to other heat modalities have not been done. For acute muscle soreness or arthritis pain, an infrared sauna may feel good during and shortly after use, but evidence that it outperforms simpler, cheaper heat sources is limited.
Skin health and collagen: emerging research with limited human data
Infrared light in certain wavelengths (particularly near-infrared, 700–1100 nanometers) has been shown in cell and animal studies to stimulate collagen production and improve wound healing. A few small human studies have found that infrared light therapy improved skin texture or reduced the appearance of scars. However, most of this research uses targeted infrared light devices, not whole-body infrared saunas, and the wavelengths and intensities differ.
A 2013 study in Photomedicine and Laser Surgery found that far-infrared sauna use improved skin hydration and elasticity in 20 healthy volunteers over eight weeks. The effect was modest, and the study did not include a control group, so it cannot rule out placebo or natural variation. For skin health, the evidence is suggestive but not conclusive, and any benefit appears to be modest and temporary. Consistent sun protection and moisturizing remain the evidence-based foundations of skin care.
Who should avoid infrared saunas or use them cautiously
Infrared saunas raise core body temperature and increase cardiovascular stress, which is safe for most healthy adults but risky for certain groups. People with uncontrolled high blood pressure, a history of heart attack or stroke, or arrhythmias should consult a cardiologist before using an infrared sauna. Pregnant women should avoid them because elevated core temperature in early pregnancy has been associated with birth defects in animal studies, and human data are sparse. People taking medications that affect heat regulation (some antipsychotics, anticholinergics) or those with conditions that impair sweating (cystic fibrosis, certain neuropathies) should also check with a doctor first.
Dehydration is a real risk during sauna use. Drink water before, during, and after a session, and stop if you feel dizzy, nauseous, or faint. Do not use an infrared sauna while under the influence of alcohol or drugs that impair judgment, as you may not recognize warning signs of overheating. Sessions longer than 20–30 minutes are not supported by evidence and increase the risk of dehydration and heat stress without clear additional benefit.
Infrared saunas versus traditional saunas: what the evidence shows
Direct comparisons between infrared and traditional saunas are rare. Both raise core body temperature, increase heart rate, and produce sweat. Both appear safe for healthy adults when used appropriately. The main practical differences are that infrared saunas operate at lower air temperatures (which some people find more comfortable), reach operating temperature faster, and cost less to install and run than traditional saunas.
Whether one produces greater health benefit than the other is not established. A 2018 review in the Journal of Human Hypertension found that sauna use in general was associated with cardiovascular benefits in observational studies, but the review did not separate infrared from traditional saunas or account for confounding factors like exercise and diet. If you enjoy sauna use and have no medical contraindications, either type is reasonable. The choice should rest on comfort, access, and cost rather than on claims of superior health outcomes, because the evidence does not yet support one over the other.
Frequently Asked Questions
Do infrared saunas really remove toxins through sweat?
No. Toxins are eliminated by your kidneys and liver through urine and feces, not through sweat. Sweat is mostly water and salt. While infrared saunas do make you sweat, the sweat itself does not contain meaningful amounts of toxins. Any feeling of cleansing is likely due to relaxation and improved circulation during the session, not toxin removal.
Can infrared saunas help with weight loss?
Infrared saunas raise heart rate and metabolic rate during use, similar to moderate exercise. However, the calorie burn is modest—roughly equivalent to a brisk walk—and any weight loss is temporary water loss that returns when you rehydrate. Regular sauna use alone does not produce lasting weight loss without changes to diet and exercise.
How often and for how long should I use an infrared sauna?
Most studies that found benefit used sessions of 20–30 minutes, two to four times per week. Longer sessions are not supported by evidence and increase dehydration risk. Start with shorter sessions (10–15 minutes) if you are new to sauna use, and increase gradually as your body adapts. Always drink water before and after.
Is it safe to use an infrared sauna if I have high blood pressure?
Infrared saunas raise blood pressure during use, so uncontrolled high blood pressure is a reason to avoid them. If your blood pressure is well-managed with medication, ask your doctor whether sauna use is safe for you. Do not use a sauna as a substitute for blood pressure medication.
Can infrared saunas improve circulation?
Yes, during and shortly after use. Blood vessels dilate to cool your skin, increasing blood flow to the surface. However, whether this produces lasting improvements in circulation or cardiovascular function is not established. The effect is temporary and similar to what happens during or after exercise or in a traditional sauna.