Why we should use the sauna, or at least one of its alternatives, EVERY DAY

Sweating regularly halves the risk of early death from any disease

At least 20 minutes in the sauna produces reactions in the body as if you were exercising at medium intensity.

Health benefits of exposure to elevated temperatures include improved heart health, mental health, immune system function and more.

According to the Mayo Clinic Journal in the United States, people who use the sauna regularly have lower levels of heart disease, lung disease, fewer problems with blood pressure, cognitive problems or other mental problems. ( 1 )

In studies conducted in Finnish saunas, the session involved between one and three entries into the heat and lasted at least 20 minutes at an average temperature of 80ºC with short intervals for cooling down.

As I mentioned in a previous article, older men are incredibly benefited by this practice. In fact, those who used the sauna 4-7 times per week showed a 60% reduction in age-related diseases compared to those who did it 2-3 times per week (22% reduction) and compared to those who did it 1 time per week. Men benefited more from more sessions and longer duration in the sauna. ( 2 )

Direct health benefits of using the sauna frequently

Cardiovascular health

Dr. Rhonda Patrick has conducted extensive research and experiments confirming that heat exposure induces a protective response against biological processes that impair cardiovascular fitness and related disabilities. Some of the protective responses that heat exposure provides are similar to those elicited by exercise.

For example, heart rate should increase up to 100 beats per minute during a moderate sauna session and up to 150 beats per minute if it is hotter and these increases are the same as those observed during a moderate cardiovascular workout. ( 3 )

In another study Ms. Patrick mentions, involving 19 healthy adults, the effects of a 25-minute sauna session were compared to the cardiovascular effort of a moderate exercise session. During both the exercise and sauna sessions, participants' heart rates and blood pressure increased immediately, but after both sessions, both heart rates and blood pressure dropped to baseline levels measured before exercise or the sauna. Like exercise, frequent sauna use improves blood pressure, endothelial function, left ventricular function, and reduces inflammation.

Inflammation

Inflammation is a crucial element of the body's immune response that involves immune cells, cell signaling proteins, and proinflammatory factors. Acute inflammation occurs after a minor injury or infection and is characterized by redness, swelling, and fever. Chronic inflammation occurs at the cellular level in response to toxins or other stressors that cannot be easily detected. Inflammation plays an important role in the development of many chronic diseases such as cancer, cardiovascular disease, and diabetes.

C-reactive protein is one of the indicators of the inflammatory response. C-reactive protein is associated with the development of atherosclerosis, loss of arterial elasticity and incidence of cardiovascular events. Sauna use reduces blood levels of this protein. According to a study conducted on more than 2000 men in Finland, C-reactive protein levels were inversely proportional to the frequency of sauna use, i.e. lower levels of C-reactive protein the more sauna use occurred. ( 4 )

Cognitive and mental health

Both heat stress and exercise increase the expression of brain-derived neurotrophic factor (BDNF), a protein that acts on neurons in the central and peripheral nervous systems to promote the growth of new neurons. BDNF modulates neuronal plasticity and alleviates both anxiety and depression resulting from stressful events at an early age. ( 5 )

BDNF is activated in the hippocampus, cerebellum and basal forebrain which are areas involved in learning, long-term memory and executive function. BDNF is also produced in exercising muscle tissue where it plays a role in muscle repair and growth of new muscle cells. ( 6 )

Levels of attention and concentration

There are two hormones involved in mental and cognitive functioning, norepinephrine which is produced in the brain and prolactin which is released by the pituitary gland. Norepinephrine increases concentration and attention, while prolactin promotes the growth of myelin which makes the brain function faster, a key element in repairing damaged nerve cells.

When a group of young men were subjected to 80ºC of heat to subjective exhaustion, their norepinephrine levels increased by 310% and their prolactin levels by 900%. Cortisol levels (a hormone released in response to stress) decreased slightly. Similarly, a study of women who participated in sauna sessions of just 20 minutes twice a week experienced an 86% increase in norepinephrine and a 510% increase in prolactin after the session. ( 7 )

Metabolic and hormonal function

The sauna promotes the production of growth hormone, which varies according to time, temperature and frequency.

For example, repeated full-body exposure to sauna has increasingly profound effects by stimulating growth hormone production at the end of the session: 17 men and women were exposed to two one-hour sessions at 80°C per day for 7 days and showed up to a 16-fold increase in growth hormone production starting on the third day. The growth hormone effects generally persisted for up to a few hours after the session. ( 8 )

It is worth noting that the use of the sauna together with exercise can cooperate to raise the production of growth hormone significantly. ( 9 )

Glucose and insulin

Insulin regulates the glucose balance in the body primarily by promoting glucose uptake in muscle and adipose tissue. Repeated treatment with infrared sauna (another form of sauna) has been shown to significantly lower blood glucose levels. ( 10 )

In another study where insulin-resistant diabetic rats were subjected to heat treatment for 30 minutes, three times a week, for 3 months, the animals experienced a 31% decrease in plasma insulin levels and a significant reduction in blood sugar levels, suggesting insulin re-sensitivity. ( 11 )

Hyperthermia (sauna) treatment aimed directly at skeletal muscle increases the expression of a transmitter known as GLUT4, responsible for transporting glucose to skeletal muscle from the bloodstream. ( 11 ). You should know that glucose deficiency in skeletal muscle is one of the mechanisms that causes insulin resistance.

Physical condition and athletic performance

Thermal stress when using the sauna is intended to modulate the improvements achieved in physical conditioning and athletic performance by increasing endurance, as well as promoting and maintaining the development of muscle mass.

 Increased physical endurance

Sauna use for 30 minutes twice a week for 3 weeks after training was found to increase running endurance by up to 32% in 6 long-distance runners compared to measurements taken before incorporating post-workout hyperthermic therapy.

This improvement in performance was accompanied by a 7.1% increase in plasma volume and a 3.5% increase in red blood cells.

During exercise, red blood cells transport oxygen from the lungs to the tissues (especially those of the exercising muscles) and carry CO ₂ to the lungs to be exhaled. The increase in red blood cells facilitates these processes and improves the performance of the body. ( 12 )

Adaptation to heat

During exercise, body temperature increases, which decreases the body's endurance and accelerates exhaustion. The process of heat adaptation (the body's response to elevated temperature) and acclimatization induce physiological adaptations that improve thermoregulation, attenuate physiological effort, and enhance athletic performance in high temperatures. These adaptations are achieved through improved thermoregulatory and cardiovascular mechanisms of the body that reduce the harmful effects associated with elevated body temperature and optimize body function when confronting increases in body temperature during exercise.

In a study of 9 female athletes who sat 20 minutes a day for 5 days at a temperature of 50ºC with low humidity (sauna environment), they experienced improvements in their cardiovascular, thermoregulatory and perceived exertion systems compared to the control group. ( 13 )

The adaptation achieved through the sauna increases plasma volume and blood flow to the heart, resulting in a reduction in cardiovascular effort and heart rate when facing the same physical effort. These physical improvements have been observed in both high-performance athletes and in untrained people. ( 14 ) ( 15 )

Maintaining muscle mass

Muscle atrophy, reduction or shrinkage of tissue, occurs due to prolonged immobilization or disuse following sports injuries. The same occurs in older people, where the loss of muscle mass due to age is called sarcopenia.

Maintaining muscle mass requires a balance between the synthesis of new protein in the body and the breakdown of existing protein in the body. New protein synthesis occurs when the muscle is used during exercise, while protein breakdown occurs both when the muscle is being used and when it is not.

Heat adaptation through sauna use may reduce the amount of protein breakdown during disuse by increasing heat shock proteins (HSPs), reducing oxidative damage, promoting growth hormone production, and improving insulin sensitivity. ( 16 ) Maintaining effective protein synthesis is relevant when recovering from injury as injury and sarcopenia can tip the balance toward protein breakdown and promote muscle atrophy.

The sauna can be an excellent alternative for people with limitations in performing physical activities due to injuries or other conditions, since the physiological responses when using the sauna are similar to those produced by doing moderate-vigorous exercise.

In a human study, it was determined that daily use of heat treatments applied locally to the muscle during 10 days of immobilization prevented the loss of mitochondrial function, increased the levels of HSP or heat shock proteins and attenuated skeletal muscle tissue atrophy by 37% compared to the control group.

Increased heat shock proteins (HSPs), on the other hand, can prevent muscle protein damage by directly scavenging reactive oxygen species (ROS) and by strengthening the antioxidant capacity of cells through their effects on maintaining endogenous antioxidant glutathione. Furthermore, heat shock proteins can repair damaged or misfolded proteins, ensuring that proteins maintain their proper structure and function.

Sauna for detoxification

Sweating facilitates the excretion of certain toxins that bio-accumulate in muscle, adipose tissue and human organs. Sauna induces substantial sweat loss and it has been determined that a person can eliminate up to 0.5 L of sweat in the sauna, approximately. ( 17 )

Heavy metal detoxification

Daily exposure to certain heavy metals is virtually unavoidable. For example, arsenic is found in various agricultural products, cadmium in cigarette smoke and car exhaust, lead in some toys, and mercury in dental amalgams and fish. Some heavy metals can be eliminated through sweat, a process facilitated by sauna use.

In a comparative study, it was examined whether some heavy metals were better eliminated from the body via urine, blood or sweat and it turned out that greater excretion of aluminium, cadmium, cobalt and lead were eliminated more effectively via sweat than via urine, for example. ( 18 )

Elimination of Bisphenol A or BPA

This is a chemical that is present in the manufacture of plastic products such as water bottles, soft drinks, food packaging, food and beverage can linings, dental resins and composites, and more. It should be noted that BPA is an endocrine inhibitor that usurps the action of natural hormones in the body such as estrogens, androgens, and thyroid hormones, altering the natural signaling of these hormones.

BPA accumulates mainly in human adipose tissue, but some studies indicate that it is excreted through sweat and, to a lesser extent, through urine. ( 19 ) For this reason, the sauna should serve to facilitate the elimination of this toxin from the body.

Polychlorinated biphenyls or PCBs

It is a series of organochlorine compounds used in heat exchangers and dielectric fluids such as transformers or rectifier stations. The high toxicity of these components was eventually detected and they were banned since 1970, but due to the way they are used and their industrial applications, it has been necessary to recognize the impossibility of controlling the emissions of these products into the environment.

Due to its wide environmental diffusion, PCBs have been found in different products such as milk and its derivatives in human (and animal) adipose tissue and other organs with fat content such as the brain and liver. ( 20 )

Some of the effects on humans due to exposure to PCBs are as an endocrine inhibitor, especially in fetal development; risk of developing hypertension, malignant cutaneous melanoma and non-Hodgkin lymphoma. Some of this toxicity, although not all, can be eliminated through sweat. ( 21 )

Phthalates

Phthalates are plasticizers used in construction, automobiles, cosmetics and more. They are everywhere, present in food and drink packaging, nail polish, plastic toys, shower curtains, synthetic leather, plastic bags and even pharmaceuticals.

Phthalates have been detected in 98% of urine samples taken from populations around the world, including pregnant women. Phthalates have a short half-life in the body, but the problem lies in chronic exposure rather than accumulation in the body. The effects of exposure to phthalates include decreased testosterone levels and the consequences of testosterone blockage in organs and tissues. Phthalates can be transmitted from mother to fetus through the placenta resulting in abnormal sexual development. Some phthalates can be eliminated through sweat, but not completely. ( 22 )

Sauna use and precautions

The use of the sauna or one of its alternatives (Inipi, temazcal, infrared sauna, Turkish bath) is expected to be beneficial for cardiovascular, mental, fertility and athletic health. It is a safe practice for healthy adults in general, and special populations should benefit from it under proper medical supervision.

The stress caused by sauna hyperthermia elicits hormetic responses (low-dose stimulation resulting in increased tolerance eventually) driven by molecular mechanisms that protect the body from damage similar to that produced by moderate-vigorous intensity exercise and counteract the effects of aging.

Precautions include :

Children : The sauna is for healthy children over 2 years old and under adult supervision.
Pregnant women: Pregnant women who have toxemia or preeclampsia should refrain from this practice during pregnancy.

People taking medication : check that the medication has no contraindications. If in doubt, consult your doctor or the person in charge of providing the sauna service. Anyone who has been diagnosed with a cardiovascular disease should consult their doctor before using the sauna.

Tips :

Proper hydration is essential to be able to use and acclimatize to the high temperatures of the sauna. Also, electrolytes such as sodium, chloride, potassium, magnesium and calcium are lost through sweating and the body must be replenished after the session. Fatigue and muscle cramps are associated with dehydration and electrolyte deficiencies.

People who use saunas should drink plenty of fluids before and after use, as well as eat foods rich in electrolytes such as cooked spinach, avocado, tomatoes, nuts and seeds.

Alcohol should not be consumed before or during sauna use.