7 Surprising Benefits of Sauna Heat

Heat works through several mechanisms to boost cardiovascular, metabolic, and mental health, as well as longevity.

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Kayla Barnes-Lentz gave up her sauna for three months, just to see what would happen.

Recognized as one of the most publicly measured women in health optimization, Barnes-Lentz has built her home around health devices and biometric tools. However, if she had to keep only one part of her extensive and heavily researched health protocol, she said, it would be the one often enjoyed with friends or a book—her 25-minute daily sauna session. She and her husband are so committed to the practice that they eventually bought the sauna company that makes her unit.

“Outside of mastering the basics—exercise, nutrition, stress reduction, social connections, sleep, and environment optimization—sauna is the most science-backed intervention that we have for longevity,” Barnes-Lentz told The Epoch Times.

“A common misunderstanding is that sauna is only relaxation or luxury,” Finnish cardiologist and researcher Dr. Jari Laukkanen told The Epoch Times in an email. Yet this Finnish tradition, which requires little more than sitting still while the body heats up, activates and revs up our body’s cardiovascular, nervous, immune, mental, and metabolic systems—and is associated with better outcomes in disease and aging.

Heat Improves Our Resiliency

Adaptation is one widely accepted explanation for heat’s benefits. “Sauna as a mild or moderate stressor can trigger adaptive responses that make the body more resilient,” Laukkanen said.

Heat stresses the body, which adapts through multiple pathways aimed at improving function under pressure. Laukkanen described the sequence: The body’s temperature rises, heart rate spikes, blood vessels widen to send blood to the skin’s surface for cooling, skin glands activate, and we sweat; white blood cells circulate more widely, and an anti-inflammatory cascade initiates repairs to bring the body back to balance.

What we feel is a small dose of pain mixed with pleasure. The reason is that when heat becomes uncomfortable, the nervous system cues the body to release adrenocorticotropic hormone and beta-endorphin, stress-related hormones. Adrenocorticotropic turns on the stress hormone cortisol, and the beta-endorphins act as natural pain relief, followed by a sense of euphoria that often peaks at the end of a sauna session, comparable to a “runner’s high.”

Because stress plays a role in many diseases, the stress-relieving role of heat alone could be why its use is associated with many health benefits. However, there are other mechanisms, too.

Sauna Use Associated With Longer Lifespan

Frequent sauna use is associated with lower risk of death from any cause, because heat exposure appears to be protective for the cardiovascular system and mimics some low- to moderate-intensity exercise.

Compared to men who saunaed once per week, men who saunaed two to three times per week had a 23 percent lower risk of all-cause mortality, and those who saunaed four to seven times a week had a 37 percent lower risk of all-cause mortality, according to the results of a study published in JAMA Internal Medicine.

Taking a sauna and other strategies for heating up the body could be a meaningful part of reducing public health risks, Laukkanen said. “It is also scientifically fascinating because our epidemiological findings raised a much deeper biological question: Why might sauna bathing be linked to better health outcomes?”

Some initial findings show that long-term sauna use is associated with lower blood pressure and enhanced left ventricular function, while a single sauna session can raise the heart rate similar to exercise.

Sauna Use Linked to Lower Stroke and Heart Disease Risk

Finnish saunas, which use dry heat common in traditional saunas, appear to modulate cardiovascular risk factors such as cholesterol and triglyceride levels, blood pressure, inflammation, and vascular endothelium function, or how vessels control blood flow, clotting, and inflammation, according to a review published in Mayo Clinic Proceedings.

“These systems are deeply connected,” Laukkanen said. “Improved vascular function may reduce cardiovascular risk. Lower systemic inflammation may be relevant to cardiometabolic, respiratory, and brain health. And improved autonomic balance may influence recovery, stress, sleep, and well-being.”

Using a sauna four to seven times a week resulted in a 61 percent reduction in strokes, according to a study of 1,628 men and women between the ages of 53 and 74 published in Neurology.

Heat Shock Proteins May Protect the Brain

Heat shock proteins, a cellular defensive mechanism activated by heat, may play a role in how heat benefits the body, especially the brain. These proteins help repair misfolded proteins in the cells, such as those that clump together into plaques and destroy brain cells in Alzheimer’s and other neurodegenerative diseases.

Using a sauna showed a protective effect on dementia and Alzheimer’s disease that grew stronger with frequency, with four to seven times a week showing a 66 percent reduction in risk, in a study published in Age and Ageing.

At 35, Barnes-Lentz already has her mind set on preventing dementia. Growing research in this area, she said, motivates her to continue daily sauna use. “Two-thirds of all Alzheimer’s diagnoses are women, and we know that sauna could be very helpful for women, so that’s another big reason why I’m excited to keep my protocol forever,” she said.

Heat shock proteins also appear to be protective against cancer and cardiovascular disease in early research. Their role in autoimmune disease is more complicated, since they’re tied to both pro- and anti-inflammatory responses, though heat exposure appears promising for arthritis, Type 1 diabetes, lupus, and spondylarthrosis (arthritis of spine).

Heat Exposure May Lower Depression Symptoms

Heat is associated with lowering depression symptoms, perhaps through its mood-enhancing and stress-reducing benefits. However, it could also be because heat affects physical conditions underlying depression.

Pain reduction, better sleep, modulation of the nervous system, lower inflammation, adaptation to temperature changes, and better resilience to stress were all statistically significant findings that correlated with reductions in depression scores among those undergoing heat therapies, according to a meta-analysis published in the Journal of Affective Disorders Reports.

Types of heat in the studies analyzed included saunas, hot springs, hot baths, and whole-body heating devices. The findings show that heat could be an effective alternative or adjunct to pharmacological or psychological depression treatments, the authors noted.

Heat Therapy Improves Some Metabolic Markers

While heat therapy didn’t make muscles more sensitive to insulin, as researchers had hypothesized, resting in a warm room for four to six hours daily helped participants’ livers better regulate blood sugar, according to a small study published in Acta Physiologica. The authors speculate that heat lowers fat in the liver, which is a contributing factor to fatty liver disease and poor blood sugar control. Eleven participants had reduced cholesterol and circulating fats, as well as increased fat burning after 10 days of mild but prolonged heat exposure, potentially because their livers shifted to burning fat as fuel.

Other studies are conflicted on whether heat might be useful for patients with Type 2 diabetes, obesity, or other metabolic issues. However, it’s common for patients with diabetes to have lowered expression of heat shock proteins, particularly in muscle and fat. Heat exposure, as well as exercise, can help restore heat shock protein function.

Sweating May Help Excrete Toxins

Sweating out toxins is a popular wellness claim, but a lack of appropriate studies leaves the concept a bit hazy. Studies have found that sweat after sauna use contains heavy metals; however, it’s unclear if heat offers a meaningful reduction in the body’s overall toxic burden.

Some evidence points to sweat as being superior to urinating for removing certain toxic chemicals such as flame retardants, pesticides, bisphenol-A (BPA), and phthalates from the body.

Given the uncertainty, Barnes-Lentz took her own measurements, testing her total toxin burden before and after her three months without sauna use. She wasn’t surprised by the results: Her overall environmental toxins had risen.

As part of her overall longevity goals, she detoxifies from chemical and biological exposures through diet, regular exercise, and even a cross-country move away from wildfires to improve her health. Environmental toxins that build up in the body can cause cellular damage that impacts energy and organ function. Long-term exposure may cause progressive neurological degeneration.

That’s why Barnes-Lentz specifically sought a sauna from a company that avoids wood glue and polyurethane that can off-gas when the sauna gets hot.

The Nuances of Heat–and Why It Matters

The benefits of heat therapy may come best through measured exposure.

“Too little heat may not create a meaningful stimulus. Too much heat, or heat exposure in the wrong setting, can be harmful,” Laukkanen said. “The benefit appears to come from repeated, tolerable, controlled exposure, not from extreme heat.”

To date, the strongest long-term evidence comes from Finnish sauna use, with a temperature around 158 to 212 degrees Fahrenheit for 10 to 20 minutes per session and four to seven sessions weekly.

The temperature should be hot but tolerable, Laukkanen said. Drinking plenty of water, cooling yourself afterward, and being in tune with how you feel so you can avoid heat-related illness are all important. Anyone with unstable cardiovascular disease such as heart valvular disease, high or low blood pressure, or acute illness should discuss heat therapy with their doctor.

Other forms of heat therapy—hot baths, sitting in steam rooms, and using infrared therapy and saunas (110 to 135 degrees Fahrenheit), and Japanese Waon therapy, which pairs infrared heat with wrapping in a warm blanket—may offer related benefits, though the evidence base varies by method.

“The biological overlap is plausible, but we should be careful not to assume that all heat therapies have the same evidence base or the same effects,” Laukkanen said.

While taking saunas is often compared to exercise in terms of the cardiovascular and stress-response benefits, exercise involves muscle contraction, motility, and mechanical loading on joints, bones, and muscles—benefits that cannot be derived from heat, he said. Laukkanen’s message to patients is to exercise when possible, and use saunas for added benefits. “Another misunderstanding is that sauna is a cure-all. It is not,” he said. “Sauna is not a replacement for a healthy lifestyle, but it may be a powerful addition to preventive health.”