By Dr. Mercola
Sweating is a biological imperative that has a wide range of health benefits. In fact, unless you have untreated hypothyroidism, sweating is one of the indicators that will tell you that you are effectively doing a high-intensity exercise. Science has shown sweating it out in a sauna can also help:1,2
Lower blood pressure; improve blood circulation and vascular function
Boost brain health and reduce your risk of dementia
Kill disease-causing microbes
Improve mitochondrial function
Boost immune function by increasing white blood cell, lymphocyte, neutrophil and basophil counts
Reduce aches and pains, including headaches
Lower inflammation and reduce oxidative stress3
Enhance relaxation, well-being and boost mood
Improve symptoms associated with asthma, bronchitis and chronic obstructive pulmonary disease5
How Sauna Bathing Benefits Your Heart and Cardiovascular System
Research has even shown that regular sauna use can help improve athletic performance, and correlates with a reduced risk of death from any cause, including sudden death from a cardiac event.7 Among the most notable benefits associated with sauna bathing is its ability to protect and improve cardiovascular health, much in the same way exercise does.
A number of studies have shown sauna bathing lowers blood pressure, for example, which in turn lowers your risk for more serious cardiovascular events. Most recently, a study8,9,10,11 published in the American Journal of Hypertension, which had a follow-up period of nearly 25 years, found men who used the sauna for about 20 minutes four to seven times a week had nearly half the risk of hypertension (defined as blood pressure above 140/90 mmHg) compared to those who used the sauna just once a week.
Even increasing the number of sessions from one to two or three times a week cut the risk of hypertension by 24 percent. There are a number of reasons for these beneficial effects. As reported by Time magazine:12
“Co-author Dr. Jari Laukkanen, a cardiologist and professor of medicine at the University of Eastern Finland, says that sauna bathing can increase body temperature by up to 2 degrees Celsius (about 3.5 degrees Fahrenheit). This can cause blood vessels to dilate … decreasing blood pressure and helping blood flow easier …
Sauna bathing can also increase resting heart rate to 100 to 150 beats per minute, he says (up from the average 60 to 100 beats, according to the American Heart Association), improving pumping power. Sweating can also remove fluid from the body, which may contribute to decreased blood pressure levels. Plus, the authors say, spending time in the sauna likely helps people relax — both physically and mentally — and may protect against the harmful effects of stress.”
Other Research Shows Daily Sauna Significantly Decreases Risk of Cardiac Death
Another study published in 2015 found similar if not even better results.13,14,15,16,17 Here, more than 2,300 middle-aged men in eastern Finland were followed for an average of 21 years. The frequency of sauna use, and length of time spent in the sauna, correlated with a lowered risk for lethal cardiovascular events. Sauna use was also associated with a reduced risk of death from any cause, and the more they used the sauna, the better. Here they found that:
- Men who used the sauna four or more times per week cut their risk of sudden cardiac death by 63 percent, and their risk of death from coronary artery disease by 48 percent, compared to those who only used it once each week
- Those who used the sauna two to three times a week had a 22 percent lower risk of sudden cardiac death and a 23 percent lower risk of death from coronary artery disease, compared to those who used it only once a week
- Longer sessions were also beneficial. Compared to those whose sauna sessions lasted less than 11 minutes, men who spent more than 19 minutes per session in the sauna were 52 percent less likely to experience sudden cardiac death
- Overall, 10 percent of those who used the sauna just once per week suffered sudden cardiac death during the study; 8 percent of those who used the sauna two or three times week died in cardiac-related events; whereas only 5 percent of daily sauna goers suffered a lethal cardiac event
Sauna Bathing Is a Great Fitness Aid
Just like high-intensity exercises, sauna bathing also increases nitric oxide (NO). In addition to being a potent vasodilator, NO also stimulates your brain, kills bacteria, defends against tumor growth, and helps boost muscle growth and strength,18 the latter of which is one of the explanations for how sauna bathing helps improve fitness and athletic performance. As reported by Chris Kresser:19
“In a cross-over study, runners had better endurance and higher plasma red-cell volume after regular sauna therapy. Cyclists also benefited from sauna therapy, shown by increased plasma volume and better heart rate recovery after a cycling test …
A lot of what the body experiences in a sauna is similar to what happens during exercise — increased heart rate, nitric oxide, acute metabolic rate, and oxygen consumption, to name a few. Many of the benefits of saunas discussed above are also benefits of regular exercise, probably not coincidentally.”
Part of the benefit can also be attributed to thermogenesis. Exposure to extreme temperatures, be it hot or cold, actually improves mitochondrial function. When your mitochondria are not working properly, your body’s ability to generate energy is impaired. The key is to eliminate old mitochondria and create new ones — a process known as mitochondrial biogenesis.
There are a number of strategies that can do that, including exposure to extreme hot and cold temperatures, exercise and intermittent fasting (time-restricted feeding). All of these strategies stimulate the peroxisome proliferator-activated receptor-gamma co-activator 1 alpha (PGC-1 alpha), which is the primary driver for mitochondrial biogenesis. And when it comes to maintaining biological functioning and good health, the more mitochondria you have the better.
Heat Stress Improves Fitness
Exercise and sauna bathing both generate heat stress as well, which activates genes that are important for optimizing heat shock proteins (HSP) inside your cells. Like mitochondria, these proteins get damaged with time and need to be renewed.
Accumulation of damaged HSP can lead to plaque formation in your brain and/or vascular system. Heat stress helps prevent this. HSP are also involved in longevity, and are important for preventing muscle atrophy. Hyperthermic conditioning (i.e., acclimating yourself to heat independent of aerobic physical activity through sauna use) has also been shown to boost athletic endurance, by:
- Increasing plasma volume and blood flow to your heart, which reduces cardiovascular strain and lowers your heart rate during exercise
- Increasing blood flow to your muscles. By delivering more nutrients such as glucose and oxygen to your muscles, fatigue is reduced
- Improving thermoregulatory control and increasing sweat rate, thereby allowing your core body heat to remain lower even during high exertion. Once you’re heat acclimated, sweating occurs at a lower body temperature than previously, and you sweat longer
Sauna Bathing Benefits Your Brain as Well
Like exercise, sauna use has been shown to boost brain health as well, in part by lowering inflammation, improving vascular function, enhancing relaxation20 and eliminating toxins. Earlier this year, researchers reported that men who used a sauna four to seven times a week for an average length of 15 minutes cut their risk of dementia and Alzheimer’s disease by 66 and 65 percent respectively, compared to those who used the sauna only once weekly.21
These results held true even after other healthy lifestyle factors were taken into account, such as exercise and socioeconomic factors. Other research22 has shown sauna use increases levels of norepinephrine, a stress hormone that increases focus and attention, as well as prolactin, which may promote myelin growth, helping your brain to function faster and repair nerve cell damage.
Researchers have also found a link between heat exposure and brain-derived neurotrophic factor (BDNF),23 which activates brain stem cells to convert into new neurons. BDNF also triggers numerous other chemicals that promote neural health. Heat stress also benefits your brain by:24
- Preventing aggregation of proteins in your arteries and brain
- Increasing production of dynorphin, which helps cool your body down. Although dynorphin has the opposite effect of endorphins, it sensitizes your brain to endorphins that your body produces
- Increasing production of growth factors, which in turn promote the growth of brain neurons
Sauna Bathing Is an Important Detox Strategy
Sauna bathing also benefits health by boosting elimination of toxins,25 including pesticides and heavy metals such as cadmium, arsenic, lead and mercury.26 Infrared saunas (which I’ll discuss further below) are particularly good for this. By heating your tissues several inches deep, the infrared sauna enhances your natural metabolic processes, blood circulation and tissue oxygenation.
Lack of sweating may actually result in an increased toxic load over time, which in turn can adversely affect your heart and brain. Compared to other detoxification strategies, sauna bathing has a number of benefits, and may be one of the best, if not the best, strategy to lower your toxic load in a natural way.
As discussed in my interview with Dr. George Yu, the mobilization of stored toxins can be further enhanced by taking niacin (vitamin B3). The niacin helps mobilize fat, freeing up toxic chemicals locked in lipophilic tissues such as your brain. When the niacin is taken in conjunction with sauna bathing, the mobilized toxins can then be safely eliminated through your sweat.
General Sauna Recommendations
If you've never taken a sauna before, start out by spending only four or five minutes in there and work your way up to somewhere between 15 to 30 minutes. You will lose important body electrolytes when you do a sauna so it is important to make sure you supplement with extra salt. Either salt your food more, or put a half-teaspoon of Himalayan salt in 2 ounces of water and flavor it with lemon or lime juice and use it as salt shot.
Even if you can comfortably tolerate the heat, the detoxification process can in some cases be severe, depending on your toxic load. If you experience detox symptoms or feel ill after sauna bathing, try cutting down on the time you spend in there and slowly work your way up. That said, here are some general recommendations for using the sauna:
- Infrared sauna: 160 to 180 degrees F for 15 to 30 minutes
- Regular (Finnish wet or dry) sauna: 180 to 190 degrees F for 10 to 20 minutes
Additionally, consider the following safety tips at all times:
Avoid using a sauna by yourself; always sauna with a buddy
Always listen to your body when deciding how much heat stress you can tolerate. If you’re ill or heat-sensitive, decrease the temperature, time spent in the sauna or both
Do not use a sauna if you've been drinking alcohol
Be sure to drink plenty of pure water before and after your sauna session. To replace electrolytes use Himalayan salt as discussed above
Avoid saunas during pregnancy
You may want to rest either sitting or lying down for about 10 minutes afterward
Different Types of Saunas
There are several types of saunas to choose from, and they all work in different ways:27
- Finnish wet sauna, in which water is tossed on hot coals, generating ample amounts of steam and humidity
- Finnish dry sauna, oftentimes electric, which prevents the use of water
- 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 that the far-infrared sauna is able to heat you from the inside out. Compared to traditional saunas, athletes using infrared saunas also report greater recovery from strength and endurance training sessions.28
Near-Infrared Radiation Is Important for Optimal Health
The near-infrared range affects your health in a number of important ways,29 primarily through its interaction with chromophores — light-absorbing molecules found in your mitochondria and in water molecules.
In your mitochondria, there's a light-absorbing molecule called cytochrome c oxidase (CCO), which is part of the mitochondrial electron transport chain and absorbs near-infrared light around 830 nm. CCO is involved in the energy production within the mitochondria. Adenosine triphosphate (ATP) — cellular energy — is the end product.
ATP is the energy currency of your body and is needed for nearly all metabolic activities, including ion transport, synthesizing and metabolism. Light is actually an important and necessary fuel for your body, much like food. When you expose your bare skin to near-infrared light, the CCO in your mitochondria are enhanced and increase their ATP production. Near-infrared light is also profoundly healing, and helps optimize a number of other important biological functions.
The absence of near-infrared wavelengths in artificial light sources like commercial lighting LEDs and fluorescent lights is what makes these light sources so hazardous to your health.
While I still highly value regular exposure to near-infrared radiation, I used to believe that near-infrared saunas with heat lamps were a useful way to achieve this but now I understand that while they do produce valuable near infrared frequencies, that is only 10 percent of their output, and the far hotter far-infrared frequencies prevent you from getting close enough to the bulb to achieve a therapeutic benefit.
So, I personally now use an LED light bed that consists of red (660 nm) and near infrared (850 nm). Since there are no frequencies higher, very little heat is generated and you can get close enough to the bed to get a healthy therapeutic dose. You can achieve similar benefits with the sun, but of course most don’t have access or the time to access the sun regularly, and on most of their skin. I personally use it in addition to regular sun exposure as I feel there are additional benefits.
Important Caveats and Precautions
If using a far-infrared sauna, make sure it emits low electromagnetic fields (EMFs). Also, regardless of which type of sauna you use, keep in mind that profuse sweating will cause depletion of important minerals such as magnesium.
Finally, men may consider protecting their testes by holding an ice pack wrapped with a cloth near their scrotum while sauna bathing, as the testes were not designed for such high temperatures. While sauna bathing is by and large hailed as profoundly beneficial, there have been reports of impaired fertility in men who use sauna regularly. I personally use a tent sauna so my head is outside of the sauna and does not heat up, and I sauna well over 300 days a year.
In summary, regular sauna therapy can be a powerful tool to optimize your health, helping your body eliminate toxins and energizing your mitochondria. Many gyms have saunas you can use after your regular workout, or you can purchase a low-EMF portable infrared sauna tent that takes up very little room once folded together. It’s an investment that can pay serious health dividends over time.