Spending Time in a Sauna Can Reduce Your Risk for a Stroke

sauna benefits

Story at-a-glance -

  • Saunas are not as popular in America as they are in Finland, where they may be as widespread as television sets, and demonstrate the potential to significantly reduce your risk of stroke with consistent use
  • Your skin is a major organ of elimination; sweating is an important way to eliminate toxins and waste products, control your body temperature and clean your pores — all benefits of sauna use
  • Additional benefits from saunas include improved cognitive function and reduced risk of dementia, pain relief, improved athletic performance, limiting cell damage and facilitating cell recovery
  • You have a choice of three main types of saunas; while all types are beneficial, near-infrared offer additional benefits based on the way your body is heated

By Dr. Mercola

In the U.S., many Americans use a sauna only while at the gym or on vacation, if at all, in contrast to people living in Finland. At least once a week, 99 percent of Finns1 take a sauna, and some far more often. The Finns value sauna use for stress relief. Known as a "poor man's pharmacy," saunas offer proven health benefits virtually anyone can enjoy.

Not surprisingly, much of the research has come from Finland where saunas are nearly as common as television sets, found in private homes, offices and even factories.2 Today, they're becoming increasingly popular with athletes for post-workout muscle relaxation and to improve athletic performance.

According to Rhonda Patrick, Ph.D.,3 increasing your core temperature for short periods, as accomplished in a sauna, may have multiple positive effects on your body, including the growth of new brain cells. As your skin is a major organ of elimination, promoting sweating with sauna use may also help you detoxify. Researchers have also linked sauna use with a reduced risk for stroke.4

Sauna Use May Reduce Your Risk of Stroke

In a study published in Neurology,5 researchers assessed over 1,600 men and women aged 53 to 74 who did not have a known history of stroke. The participants were part of the Finnish Kuopio Ischemic Heart Disease prospective cohort study and as defined by the researchers, took either one, up to three or up to seven sauna sessions per week.

At least half the participants were followed for nearly 15 years, during which 155 stroke events were recorded.6 The researchers compared individuals who used a sauna once a week against those who used a sauna up to three or up to seven times per week. After adjusting for other variables, they found those who took a sauna up to three times per week were 12 percent less likely to have a stroke, whereas those who took a sauna up to seven times a week reduced their risk by 62 percent.7

The researchers suggested sauna use may help reduce stroke risk by lowering inflammation, reducing arterial stiffness and improving blood flow through the circulatory system. These changes may be a result of an increase in body temperature during a sauna.8 The popularity of the sauna in Finland led the researchers to suggest further research was necessary to compare those who never use saunas against those who use them frequently.9

They encouraged those who have a regular sauna habit to continue as the results suggest significant benefit. However, those not familiar with sauna use should start slowly and build their heat tolerance to improve the results without heat stress on their cardiovascular system.10

Sweating Is Important

Sweating is an essential process designed to keep your body cool but also has benefits beyond temperature control. Sweating helps expel toxins, kill viruses and clean your pores, and may have other benefits as well. Your skin is a major organ of elimination, but as many do not sweat on a regular basis, using a sauna may help restore your skin's ability to eliminate toxins.

Saunas and heat baths have been a form of cleansing since ancient times. Sweating has been perceived to promote health and has been a part of worldwide traditions and customs since ancient Roman baths and Aboriginal sweat lodges. A review published in the Journal of Environmental and Public Health found:11

"Sweating is not only observed to enhance excretion of the toxic elements of interest in this paper, but also may increase excretion of diverse toxicants, as observed in New York rescue workers, or in particular persistent flame retardants and bisphenol-A … Optimizing the potential of sweating as a therapeutic excretory mechanism merits further research."

Surprising Health Benefits of Environmental Conditioning

Patrick calls this concept "hyperthermic conditioning." Exposure to extreme temperatures, hot and cold, is an effective way of boosting mitochondrial biogenesis. The strategy places stress on your body in short bouts and produces benefits in a process called hormesis, referring to exposure to very short bursts of stress such as exercise, heat, cold, fasting or antioxidants. Through short bursts, it activates a variety of response pathways preparing your body to deal with stress.12

Elevating your core temperature through exercise, steam rooms, hot baths or saunas helps optimize heat shock proteins (HSP) inside your cells, which limit cellular damage and facilitate cellular recovery.13 Accumulation of damaged HSP may lead to plaque formation in your brain or cardiovascular system, thus leading to an increased risk of stroke or cardiovascular disease.

Heat stress helps prevent this adverse chain of reactions and may be involved in increasing longevity. Heat stress may also improve athletic performance as demonstrated in one study where athletes who spent 30 minutes in a sauna after workouts, two to three times a week for three weeks, increased the time it took them to run to exhaustion by 32 percent.14

This may happen through a number of adaptations, including reduced heart rate, lower core body temperature during exercise, higher sweat rate and increased thermal regulatory control, increased plasma volume, and reduced rate of glycogen depletion through improved blood flow to skeletal muscles.15

Wim Hof, a Dutch fitness trainer, who also goes by the nickname "Iceman," has popularized another branch of environmental conditioning in which he uses ice baths.16 His argues the circulatory system is designed to adapt to different surrounding conditions.

In the face of a lack of stress on your cardiovascular system from consistently controlled temperature, it may be damaged and result in conditions such as hypertension and stroke. A study published in Nature17 revealed evidence exposure to cold temperature may transform the type of fat in your body, helping to burn off excess weight. The primary stimulus to produce this type of fat was cold exposure.

More Physical Benefits of Sauna Use

Sauna use may lower the risk of dementia,18 and may improve vascular function and your ability to improve focus and attention.19 Other research has demonstrated the ability of heat stress to promote myelin growth,20 helping your brain to function faster and repair nerve cell damage. Heat may increase the permeability of the blood-brain barrier, stimulating cerebral output of brain-derived neurotrophic factor,21 activating brain stem cells to convert into new neurons.22

Sauna use may help soothe muscle tension and is beneficial in helping your body recover from strength and endurance training sessions. In one study of 44 patients with fibromyalgia, researchers found a reduction in pain23 between 33 percent and 77 percent after use of a far infrared dry sauna. Six months after the study had concluded, the participants continued to report a reduction in pain between 28 percent and 68 percent.

Sauna use may naturally release human growth hormone (HGH), reducing serious muscle loss and atrophy occurring with aging.24 Injections of HGH are banned in nearly every professional sport due to potential side effects and long-term harm. This use is unnecessary as there are ways to naturally optimize your HGH using high-intensity exercise, intermittent fasting and saunas.

Sauna use has also demonstrated benefits for individuals suffering from asthma, bronchitis and obstructive pulmonary disease.25 Those with rheumatoid arthritis and ankylosing spondylitis report positive effects from using infrared sauna therapy, reporting less pain and stiffness after four to eight weeks of treatment.26

Your Choice in Saunas Makes a Difference

You have several types of saunas to choose from, including:27

  • Finnish sauna, either wet or dry
  • Far-infrared saunas
  • Near-infrared saunas (emitters and lamps)

The difference between an infrared sauna and the traditional Finnish-style saunas (whether wet or dry) is the Finnish-style sauna heats you from the outside in, like an oven. The infrared sauna heats you from the inside out. Infrared saunas are particularly known for their ability to promote detoxification, and the heating method is part of the reason. By heating your tissues several inches deep, the infrared sauna may enhance your natural metabolic processes and blood circulation, also helping oxygenate your tissues.

Near-infrared saunas have additional benefits over others, including far-infrared saunas. Near-infrared penetrates your tissue more effectively than far-infrared since wavelengths under 900 nanometers in the near-infrared are not absorbed by water like the higher wavelengths in mid- and far-infrared, and thus can penetrate tissues more deeply.

Benefits of Near-Infrared Saunas Beyond Heat

The near-infrared range affects your health in a number of important ways,28 primarily through interaction with chromophores in your body. Chromophores are light-absorbing molecules found in your mitochondria and in water molecules. To ensure near-infrared rays penetrate your skin, avoid wearing clothing when using a near-infrared sauna.

In your mitochondria, there's a specific light-absorbing molecule called cytochrome c oxidase (cco), part of the mitochondrial electron transport chain. Cco is involved in energy production within the mitochondria. Adenosine triphosphate (ATP) — cellular energy — is the end product. ATP is the fuel your cells need for all their varied functions, including ion transport and metabolism. Most people don't realize light is a necessary fuel, like food. When your bare skin is exposed to near-infrared light, cco increases ATP production.

Near-infrared light also has healing and repairing properties, and helps optimize many other biological functions. Its absence in artificial light sources, such as LED and fluorescent lights, is what makes these sources so dangerous to your health. We now know mitochondrial dysfunction is at the heart of most health problems and chronic diseases, including many signs of aging. For these reasons, I strongly recommend using a sauna offering a full spectrum of infrared radiation, not just far-infrared.

Regular exposure to near-infrared through the sun and/or sauna is a powerful strategy to improve your health. Beware most infrared saunas emit dangerous non-native electromagnetic fields (EMFs). Seek one emitting low or no non-native EMFs to protect your health. To learn more about this issue, please see my interview with Steve Benda below, who has spent many years developing low-EMF saunas.

Consider These Precautions Before Using a Sauna

Before you jump into the first sauna you can find, there are a few safety factors you'll want to consider:

Drink plenty of water to stay hydrated. Heat stress or heat stroke are real possibilities from excessive fluid loss. The potential for the effects of significant dehydration are higher when you use a sauna after a hard workout. Carry a water bottle, preferably protected glass, with you and drink frequently. Do not drink alcohol in a sauna as the alcohol and heat may trigger a cardiovascular event.

If you experience a headache after using a sauna or hot tub, you may want to use a cool rag over your head so your body will cool more easily. Your core temperature will still rise, but the experience may be more pleasant for you.

If you are trying to have a baby, you'll want to steer clear of the sauna. As your body heat rises, so does the temperature of your testicles, reducing your fertility. This reduces your sperm count and motility (how well sperm swim). The effect is reversible, but can take up to five weeks. You'll also want to avoid the sauna during pregnancy as it may cause fetal abnormalities.

A sauna is supposed to be relaxing and not a torture chamber. Your body is designed to function optimally at 98.6 degrees F (37 degrees C). Raising your core temperature above 104.8 degrees F (40.4 degrees C) is a medical emergency. Staying in a sauna longer than you should, or becoming severely dehydrated, can lead to death. Avoid using a sauna by yourself; always sauna with a buddy.

Steer clear of public saunas that are not thoroughly and carefully cleaned between clients. Remember, saunas detoxify your body of heavy metals, which are released in your sweat. When you enter a sauna that hasn't been cleaned you can potentially absorb the heavy metals and toxins from the previous client through your skin.

Health centers offering sauna therapy have rigorous cleansing protocols in place between each patient, which is something you likely will not find in your local gym or other places offering saunas for public use. Ideally, consider purchasing your own for use at home.