You've heard me talk about the benefits of cold exposure on our health and waist line, but what about the heat?
Saunas have been used around the world for centuries and their use is spreading with the rising popularity of infrared saunas and health centres.
In this article I look at the literature and explore the health and performance benefits of sauna use.
I provide answers to common questions around saunas - does sitting in a hot box really help with fat loss?
Can a sauna session after a workout boost performance? Or does it impair performance?
Plus I touch on a few lesser known benefits to heat exposure. For instance, did you know a sauna session can help lower pain and improve brain function?
All this plus much more is outlined below. Also, if you're looking at buying your own sauna, I have put together some notes that may help with your decision HERE.
A five year study, with a population size of 2315 Finnish middle aged men, found that those who used the sauna multiple times a week decreased their likely hood of heart disease. (1)
Great, but what if you don't have access to a sauna multiple times a week?
There were heart health benefits beginning at one sauna session a week. But the benefits increased as the frequency increased. Four to seven sauna sessions a week had the best benefits. With each session lasting 20minutes or longer.
Regular infrared sauna sessions also may protect against oxidative stress and atherosclerosis (3). This was found in a study where patients used Waon therapy (15 minutes a day for 2 weeks in a infrared sauna) (2).
Finally, one study on a small group of young males noted that 3 weeks of sauna use lowered their cholesterol markers (28).
Regular sauna sessions (15minutes a day in an infrared sauna) has been shown to reduce blood pressure (2).
Another study found that 2 sauna sessions a week over 3 months improved blood pressure in hypertensive patients (4).
Growth hormone is an important hormone for body repair, recovery and even fat loss. It is well documented saunas can increase growth hormone release.
In one study, growth hormone increased by 142% after a session in a high temperature (80-120C) Finnish sauna. One hour after the sauna session ended, growth hormone returned to baseline (5).
A 1996 study found an even greater growth hormone boost from hot saunas. Male and Females who had two high heat (80C + ) sauna sessions a day for a week increased their growth hormone by up to 2.3x (6).
And if you are after some serious growth hormone improvements, replicate the study that caused a 16 fold increase in growth hormone in as little as 3 days (12).
The only catch is you have to do two 1 hour 80C sauna sessions a day for a few days! Thats a lot of time spent in a really hot box!
It is noted that growth hormone secretion is increased by thermal stress. It appears the hotter the sauna the greater the hormone release.
This is no real surprise, but frequent sauna sessions help individuals tolerate higher temperature (9).
This is beneficial for athletes or emergency workers who compete or work in high heat environments. Or for people who hate hot climates (like me!)
The skin is the bodies largest organ. It has many jobs one of which is assisting with detoxification through sweat.
Our sweat contains many toxins and heavy metals. Arsenic, cadmium, lead and mercury are all found in human sweat (10).
Sweating has been used for centuries to help eliminate toxin exposure and this is true for today as well.
In fact, a popular detox protocol that combines infrared saunas with niacin supplementation has been shown to be an effective way to reduce stored toxins in the body (11).
Sauna use can help speed up muscle recovery. The increased growth hormone could be one factor behind this.
But in animal studies heat exposure was shown to slow muscle wastage in immobile limbs (13). While heat also helps regrow damaged muscle (14).
Saunas have many benefits for endurance athletes:
Studies have also shown that regular sauna sessions (twice a week) increased running time to exhaustion in runners (15).
Meanwhile blood plasma levels increased in endurance cyclists after four 30minute sauna sessions (17).
And 30 minutes in a sauna after exercise can increase red blood cell production to levels of someone doping with EPO (27).
Sauna use has been shown to help increase muscle size. In animals hyperthermia from sauna use elevated heat shock protein expression and increased muscle regrowth in injured muscle tissue (14).
Also, elevated heat shock proteins have been shown to protect against muscle breakdown (18).
Great for those looking to preserve muscle tissue, especially when dieting down to drop body fat levels.
Poor insulin sensitivity contributes to weight gain, inflammation and diabetes.
Heat exposure from saunas helps clear glucose from the blood and reduce insulin resistance in obese diabetic mice (19).
The heat exposure increased the expression of GLUT4 transporters - which allow glucose to be transported directly into the muscle from the bloodstream.
These GLUT4 transporters are also activated after heavy weight training (and is why I recommend weight lifting for fat loss).
Given that sauna sessions improve insulin sensitivity, help clear glucose from the blood and promote growth hormone levels, it is fair to say that saunas can indirectly help with fat loss.
Also, it's important to note that the body will store toxins (such as heavy metals and chemicals) in fat tissue.
The detoxification properties of niacin combined with infrared saunas could also help with with fat tissue breakdown and resulting fat loss. Especially fat loss in areas high in stored toxins (such as belly fat).
Note - for more on losing fat, be sure to access my FREE fat loss resource page here.
There is an epidemiological study done on 1600 middle aged people living in Finland. This study did link sauna use to improved sleep.
My own personal experience with sauna and sleep is also positive. I do find that my Oura sleep score is typically higher on nights when I have had a sauna session.
Exposing your body to extreme temperatures (hot or cold) is stressful for the body and it will raise cortisol levels.
Yet this stressful event can have a longer term beneficial change.
This is called hormesis. Think - short term pain, long term gain.
It is important to note that a sauna session is a stressful situation, and just like you shouldn't exercise at extreme intensities without adequate training, rest and repair , you shouldn't expose the body to extreme temperatures without proper adaptation and recovery.
As I mentioned, saunas cause a raise in cortisol levels (the bodies stress hormone). One study measured cortisol levels in healthy men and woman during a sauna session.
Cortisol initially decreased in the 90 degree sauna, then started increasing after 15minute. It reached it's highest level 15 minutes after the completion of the 30minute sauna (22).
However, regular long term sauna use has been shown to lower cortisol levels (23, 24). Again showing how a short term stress can have a long term health benefit.
As little as 15 minutes in a sauna will cause a immune system response - while blood cells, neutrophil and lymphocyte counts all increased (25) after the sauna session.
This aligns with the higher stress response levels noted above.
And the real benefits come from ongoing use. Regular sauna use decreases the chance of falling ill to the flu or the common cold (26).
Regular sauna sessions are effective at reducing chronic headache pain and headache intensity (20). Two groups of individuals who suffered from chronic tension headaches were given a list of treatments to help with their headache pain.
One group had a list that contained sauna treatment, the other group had the same list except for the sauna sessions.
After 8 weeks the group who were using the sauna treatments had significantly lower pain.
Another study had patients with chronic pain undergo a variety of treatments. It was found that daily infrared sauna sessions helped decrease levels of chronic pain (7).
Likewise, 2 infrared sauna sessions a week for 4 weeks helped reduce rheumatoid arthritis related pain (8).
Daily infrared sauna sessions for 35 consecutive days was used as a therapy for chronic fatigue suffers.
After 15-25 days symptoms such as fatigue, pain, sleep disturbance, and low-grade fever dramatically improved.
Although sauna administration was discontinued after 35 days, the subjects showed no relapse or exacerbation of symptoms during the first year after discharge (21).
Brain-derived neurotrophic factor (BDNF) increases when the body is exposed to heat stress. BDNF increases the growth of new brain cells while protecting existing neurons.
In turn this can help to enhance learning and even protect against anxiety and depression (29).
Anyone who has experienced a sauna session knows how good you feel afterwards.
A big reason for this is not just because of the stress response (and spike in adrenaline) but high heat exposure increases endorphin levels (30). This is the same experience as the 'runners high' endurance athletes experience.
If the reasons above aren't enough to start using a sauna, this one should. Research shows that regular sauna is linked to increased lifespan in adults (1).
In insects (worms and flies) heat exposure resulting in heat shock proteins to be activated increases lifespan by up to 15%
The evidence is rather clear - exposing our bodies to high heat may cause some discomfort, but the health benefits are highly positive!
Its for these 18 reasons why I recommend a weekly sauna session in The Program (learn more HERE).
I'm sure you this article has left you with many questions about sauna use - what is the best type of sauna to use? Should you use saunas around training? How hot should the temperature be? And much more...
But do not worry, I'm working on a epic article that will answer all of these questions. A 'Everything You Need To Know About Saunas' article! Be sure to CLICK HERE be the first to receive this article on saunas.
And if you do have any questions you would like me to cover in this article, please post them below.
Finally, if you are looking at purchasing a sauna for your home, please ensure you do some research first, as there are many inferior sauna products on the market, especially around infrared saunas.
I have done a bit of research on saunas as I'm looking at buying one myself. If you want to access my sauna buyers guide, please click HERE.
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