Benefits of Sauna For Longevity

longevity Jan 18, 2023

Article by: Inka Land, neuropsychology MSc

This science-based article tells you all you need to know about sauna bathing, its health benefits, and how to do it.

TABLE OF CONTENTS

1. What is sauna therapy
2. What is the difference between Finnish sauna and infrared sauna
3. Sauna vs steam room
4. 7 Health benefits of sauna
5. 6 Mechanisms of sauna health benefits
6. Infrared sauna health benefits
7. Can sauna be harmful?
8. Best sauna protocol
9. Summary

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What is sauna therapy?

Sauna bathing is a traditional Finnish practice of sitting in a heated room. Recently, it's also been studied as a form of heat therapy for its health benefits. It's usually done in a wooden room that’s heated up with an electric heater or red light thermal panels up to 50-80°C (120 - 175 °F).

The person sits in the room naked for about 20–30 minutes and achieves a faster heart rate, sweating, and relaxation effect from the heat.

When done regularly, it has been shown to reduce the risk of heart disease, dementia an all-cause mortality by up to 60 %. It has great benefits for cardiovascular health, immunity, tissue repair, and for stress management.

What's the difference between a Finnish dry sauna and an infrared sauna?

Dry saunas are the traditional Finnish saunas that have been used in famous Finnish sauna studies. The sauna has an electric heater or wood heater that’s topped up with stones. The sauna is heated up to 80° C or 175 °F and occasionally water can be thrown into the sauna heater to create a heat wave. The duration of a sauna session is usually about 20 minutes, but sometimes a second session is done after cooling off a bit in a cold shower or rolling in the snow. The optimal humidity of a Finnish sauna is between 10-20 % which makes it very different from, for example, a steam room, where the humidity is over 50 %.

Infrared saunas are heated with thermal red light panels and the temperature goes only to about 60°C or 140°F. The duration is similar, about 15 to 20 minutes but can be even longer up to 40 minutes. It’s easier to stay in a red light sauna longer because it is not that hot

Sauna vs steam room

Steam saunas or steam rooms are similar to saunas, but they are not particularly saunas. They are more like enclosed spaces heated with steam. The temperature is around 110°F or 40°C. The humidity is high – around 50 %, which partially prevents proper sweat evaporation. The normal sauna studies, which are associated with significant health benefits, are not done in steam rooms but instead, in dry Finnish saunas with low humidity and high temperature.

7 Health benefits of sauna

There are many scientifically studied health benefits of sauna. Read more about the specific biological mechanisms, that underly these effects, in the next section.

1. Improved heart health and reduce cardiovascular diseases

Finnish longitudinal sauna studies show that bathing in a sauna 4-7 times a week reduces cardiovascular disease mortality risk by 50 %, and all-cause mortality risk by 40 %.

2. Good for blood pressure

Sauna is associated with reduced blood pressure and shown to be good for managing hypertension. That’s why there are also warnings about sauna use for people with low blood pressure – people with hypotension can feel dizzy and even faint in too long sauna sessions.

3. Sauna Reduces Alzheimer’s Disease risk

Finnish longitudinal sauna studies show that bathing in a sauna 4-7 times a week reduces Alzheimer’s disease risk by 65 %. Heat Shock Proteins, which are elevated after sauna use, repair (mis)folded beta-amyloid and tau-proteins that can lead to the formation of amyloid and tau plaques – a well-known Alzheimer’s risk factor.

4. Sauna benefits insulin sensitivity

Sauna use has been shown to improve insulin sensitivity and boost Nitric Oxide synthase, which may aid in diabetic control.

5. Sauna has mental health benefits

Sauna has been shown to improve mood, aid relaxation, and lower the risk of psychiatric disorders. As the sauna is an empty room, it’s also clear from distractions and helps to get easier into a calm and meditative space.

In one study, a single heat therapy session reduced depression scores up to 6 weeks post-intervention compared to a sham in patients with major Depressive Disorder. There are many ongoing studies on using sauna therapy as clinical support for depression.

One longitudinal study found a strong inverse and independent association between frequent sauna bathing and the future risk of psychotic disorders in the general male population.

Sauna bathing is an opportunity to socialize or even create friendships, which decreases feelings of isolation, a factor implicated in the development of psychosis

Sauna has also been shown to improve self-assessed quality of life.

6. Sauna can reduce headaches and pain

In one study, people with chronic tension headaches reported a 44% reduction in headache intensity after 6 weeks of sauna treatment. Similarly, a Japanese study with chronic pain disorder patients found an increased return rate to work and reduced anger after sauna intervention compared to exercise therapy. This study used a far infrared dry sauna therapy and post-sauna warming.

7. Sauna has positive effects on cholesterol

Several studies show that even 2 or 4 weeks of regular sauna use can reduce total and LDL cholesterol, and improve good HDL cholesterol. Sauna Therapy can be as efficient for blood lipid improvements as moderate-intensity exercise.

6 Mechanisms of sauna

There are many biological mechanisms that sauna causes in the human body, explaining its wide-ranging health benefits

1. Sauna Activate Heat Shock Proteins

The heat, which is a stressor to the body, causes positive hormetic stress. In response to the heat, the body increases Heat Shock Proteins by 1,5 times. Their function is to repair misfolded proteins and increase muscle and brain growth factors like IGF-1 and Brain-Derived Neurotrophic Factor (BDNF). Heat Shock Protein also increases cellular autophagy, which clears off cellular “junk” or unfunctional parts of cells.

2. Preconditioning hormesis

Exposing the body to a small stressor like a sauna makes it more resilient to following stressors. For example, animals who are exposed to heat, are less harmed by later toxin exposure, because the body’s defense mechanisms and detox are already activated. This can also help with exercise because it increases tolerance to elevated body temperature.

3. Sauna Detoxes

Sauna use has been shown to increase toxin clearance from the body. In one study, policemen who were exposed to work-related toxins had improved detoxification from the toxins when treated for 4–6 weeks with infrared sauna therapy. Daily infrared sauna use also led to fewer symptoms of neurotoxicity, fewer sick days, improved sleep, and better physical health.

Sauna therapy is also part of the Hubbard protocol that’s been successfully used in detoxing toxins from veterans who suffers from symptoms of Gulf War Illness. It includes, for example, sauna therapy and the use of niacin, a form of vitamin B3 that has detox effects.

4. Increases the efficacy of beta-endorphins (the happy hormones)

Sauna is a small stressor that makes endorphin receptors more sensitive. It also increases Brain-Derived Neurotrophic Factor and causes a significant relaxation effect.

5. Increase Growth Factors

Sauna use increases growth factors that are relevant for both muscle growth factors like IGF-1 and brain growth factors like BDNF.

IGF-1 is a hormone that promotes normal growth and repair of bones and tissues around the body. It’s essential for metabolism, lipid balance, and maintenance of muscle mass.

BNDF modulates neuronal plasticity, reduced anxiety and depression, and activates the brain’s memory center hippocampus. It’s also important in executive functions.

6. Reduces cortisol

Sauna use raises cortisol during the session, probably due to discomfort, mild heat stress, and activation of the defense systems. Although, in regular sauna users, like in the Finnish population, cortisol during the session is not usually raised. But in the long term, sauna use is associated with a reduction in cortisol.

Infrared sauna health benefits

Infrared sauna therapy (also called Waon) uses less heat but has the added benefit of infrared wavelengths. There are over 5000 studies on the health benefits of red and infrared light for healing.

Infrared light can penetrate through the skin and bones and reach deep cellular structures. It activates recovery and repair processes like energy production, lowering inflammation, and helping cells to fight against oxidative stress. Infrared light waves also penetrate through the skull and activate the same healing processes in the brain tissue.

Benefits of infrared light

Increasing energy production (ATP) in mitochondria
Release nitric oxide causing vasodilation and increasing blood flow.
Reduce oxidative damage in the brain
Support brain tissue repair
Support skin elasticity and collagen production
Improve joint and tendon healing
Improve bone healing
Improve tissue healing in general
Support fat loss and healthy weight

Can sauna be harmful?

There are few reported adverse effects for sauna use when it is done safely and the heat and humidity are properly regulated.

In a review of 40 studies, only 8 reported adverse symptoms which were mainly mild and usually experienced by a single user. Mild heat discomfort was the major complaint, which could be resolved by lowering the temperature in the sauna room.

Other adverse effects of sauna included

low blood pressure
hypovolemia
polyurination
weight loss
acute bronchitis
claustrophobia experienced in the sauna room

Note that too high heat in a sauna can be dangerous and is linked to adverse health effects. For example, in a longitudinal study, bathing in a sauna in temperatures higher than 100 °C doubled dementia risk compared to bathing in temperatures at 80 °C. Severe heat stress caused by high temperatures can increase the permeability of the Blood-Brain Barrier.

Too frequent high-heat sauna use can also decrease male sperm quality and mobility due to exposing testicles to temperatures. Especially if the testicles are not properly cooled after it. Even one 20-minute sauna session at 185°F (86 °C) has been shown to reduce sperm motility and reduce sperm count for about five weeks, after which it returned to normal.

People with hypotension may get dizzy or have too low blood pressure in the sauna and needs to be aware of this. They may need to consult their healthcare professional for sauna use.

People with medical conditions should consult their healthcare professional before. sauna use.

Best sauna protocol

Studies suggest that the best health benefits are associated with the following sauna use practices

In a dry sauna (traditional Finnish sauna)

Use the sauna 4-7 times a week or at least 1 time a week
During the session, stay in the sauna for at least 20 – 30 minutes with intermittent periods of cooling
Make sure the sauna is heated between 70-80°C
Make sure the sauna has a maximum of 10-20 % humidity for proper sweating
Drink at least 1-2 liters of water interleaved before, after, and during a sauna session. You may need to replenish your minerals as well if you sweat a lot.
Don’t drink alcohol in a sauna because it increases the risk of accidents, cardiovascular distress, and dehydration

In an Infrared sauna

Heat the sauna to at least 50 degrees and stay in for 15-30 minutes per session. This can be followed by 30-minute supine lying under blankets or in a heated room
Drink water before, after, and during a sauna session

Summary

Sauna bathing is a well-researched and safe health practice for improving almost all parameters of health and lifespan. Studies on sauna health benefits are mainly conducted in Finnish dry saunas or with an infrared sauna. Dry and infrared saunas have slightly different effects on health.