Saunas and Your Health: How Heat Therapy Supports Heart, Brain, and Recovery

What is a Sauna and How Does It Work?

A sauna is a small heated room, usually kept between 150 and 195°F, where you sit and let your body warm up. In a dry Finnish sauna, the air is hot and low in humidity. Your skin temperature rises, blood vessels open, and you begin to sweat. This controlled heat stress gently challenges your heart, blood vessels, and nervous system in a way that is similar to light or moderate exercise.

The Biology of Heat: What Happens Inside Your Body

When you sit in a sauna, the heat is not just warming your skin, it is triggering coordinated responses in your blood vessels, heart, brain, and even inside your cells. As your core temperature rises slightly, your body activates the sympathetic nervous system, which increases heart rate and sends more blood to the skin to help release heat. Blood vessels in the skin and muscles widen, or vasodilate, which lowers vascular resistance and improves blood flow. This repeated bout of controlled “stress” is similar, in a mild way, to the stress of exercise and is one reason saunas can improve blood pressure and arterial function over time.

At the cellular level, heat turns on a family of protective proteins called heat shock proteins (HSPs). These proteins act like molecular chaperones. They help other proteins keep their proper shape, repair partially damaged proteins, and mark severely damaged ones for removal. HSPs are part of the body’s built in defense system against many forms of stress, including heat, oxidative stress, and inflammation. Experimental and human studies show that heat exposure and sauna use can increase circulating levels of certain HSPs, which may support better endothelial function, mitochondrial health, and resilience of the heart and blood vessels. In animal models, higher HSP activity is linked with protection against atherosclerosis and cardiac injury, and in humans, greater heat tolerance and HSP responses are associated with improved cardiovascular and metabolic health profiles.

This adaptive response is an example of hormesis, where a small, controlled stressor leads to a net positive effect by training the body to handle future stress more effectively. With regular sauna use, repeated mild heat stress can strengthen these protective pathways, which may help explain why frequent sauna bathing is associated with lower rates of cardiovascular disease, better blood pressure control, and improved markers of inflammation in long term studies.

Heat Stress and Your Cardiovascular System

When you sit in a sauna, your heart rate increases and blood vessels relax, which improves blood flow to the skin and muscles. Over time, regular sauna use has been linked to lower blood pressure, better blood vessel function, and a lower risk of developing hypertension. A large Finnish study found that people who used a sauna several times per week had lower rates of sudden cardiac death, coronary heart disease, and overall cardiovascular mortality than those who used it less often.

Meta analyses and clinical trials also suggest that repeated sauna sessions can reduce systolic blood pressure and total vascular resistance, and may improve measures of arterial health such as flow mediated dilation. These changes are especially important for people with high normal blood pressure or early vascular disease, where even small improvements can reduce long term risk.

Metabolic and Longevity Benefits

Sauna use appears to have broad metabolic effects. Heat exposure temporarily raises heart rate and energy expenditure, and regular use has been associated with better insulin sensitivity and lower levels of inflammatory markers like high sensitivity CRP in observational studies. Some long term cohort data show that frequent sauna bathing is associated with lower all-cause mortality and may blunt the higher death risk seen in people with chronic low grade inflammation.

There is also early evidence that frequent sauna use is linked with lower risks of dementia and Alzheimer disease over long follow up in Finnish men, suggesting that vascular and anti-inflammatory effects may extend to the brain as well. These findings do not prove that saunas prevent disease by themselves, but they support the idea that sauna bathing can be a useful lifestyle tool alongside exercise, nutrition, and sleep.

Brain, Mood, and Sleep

Many people report feeling calmer and more relaxed after a sauna session. Recent imaging and EEG work suggests that sauna bathing can shift brain activity toward patterns linked with relaxation and improved cognitive efficiency during recovery.

Survey based studies and small trials also suggest that regular sauna use is associated with lower anxiety, improved mood, and better sleep quality. Heat exposure can promote endorphin release, reduce muscle tension, and help the body cool more efficiently afterward, which may make it easier to fall asleep. There are also early clinical trials of whole body hyperthermia and infrared heat as add on treatments for depression, though this work is still emerging.

Pain Relief, Recovery, and Heart Failure Care

Heat relaxes muscles and increases blood flow, which can ease joint stiffness and muscular soreness after training. Some studies of passive heat therapy and infrared sauna show short term improvements in pain and quality of life in people with chronic conditions and in patients with heart failure, where carefully supervised sauna sessions improved cardiac function and symptoms.

For athletes, sauna use after aerobic training may support recovery and help maintain cardiovascular adaptations, and combining exercise with sauna appears to improve blood pressure and vascular health more than exercise alone in some trials. At the same time, very long or very hot sessions right after heavy strength training may delay muscle recovery, so timing and dose matter.

Saunas and Weight Loss: What Is Real?

You will lose weight temporarily in a sauna, but most of this loss is water from sweat, not body fat. Studies in dry Finnish saunas show an increase in calorie burn during a session, but the total is modest and does not replace regular exercise or nutritional changes. Saunas can support a healthy weight program indirectly by improving recovery, sleep, and stress, which can make it easier to stick with training and nutrition plans.

Who Should Be Careful?

For most healthy adults, 10 to 20 minute sauna sessions are safe if you hydrate and listen to your body. However, anyone with unstable heart disease, uncontrolled high blood pressure, severe valve disease, recent heart attack, or a history of fainting with heat should talk with a clinician before using a sauna. Pregnant women, people on medications that affect blood pressure or sweating, and those with kidney disease or a high risk of dehydration should also get medical advice first. Common sense rules apply: avoid alcohol, get out if you feel dizzy, and rehydrate with water afterward.

How Often and How Long?

Most research on long term outcomes has used traditional Finnish style saunas for about 10 to 20 minutes per session, at temperatures of 170°F or higher, several times per week. In the Finnish cohort studies, the largest benefits were seen in people who used a sauna 4 to 7 times per week, though even one to two sessions weekly were associated with improved cardiovascular outcomes compared with rarely using a sauna. For new users, it is reasonable to start with 5 to 10 minutes, build toward 15 to 20 minutes as tolerated, and pair sauna use with good hydration and cool down time.

How We Use Saunas in a Clinical Context

At the Performance Medicine Institute, we view sauna and other heat based therapies as one tool within a larger program that includes exercise, nutrition, sleep, and stress management. For appropriate patients we may recommend a graded sauna routine to help support blood pressure control, cardiovascular conditioning, metabolic health, and post exercise recovery, while monitoring for any signs of heat intolerance or blood pressure changes. Sauna use is not a stand-alone treatment for heart disease, obesity, or depression, but it can be a helpful add on when integrated thoughtfully into a comprehensive plan.

If you are interested in using sauna or other heat therapy as part of your health or performance program, we can help you decide if it is safe for you and design a plan that fits your training, medications, and medical history. Contact Us

References

Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and other health benefits of sauna bathing: a review of the evidence. Mayo Clin Proc. 2018;93(8):1111-1121.

Hussain J, Cohen M. Clinical effects of regular dry sauna bathing: a systematic review. Evid Based Complement Alternat Med. 2018;2018:1857413.

Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med. 2015;175(4):542-548.

Kanimozhi KK, Ravi P, Vijayakumar V, Kuppusamy M. Sauna bath reduces blood pressure in healthy adults: a meta-analysis of RCTs and quasi-experimental studies. Adv Integr Med. 2025;12(1): 2-6.