Evidence Backed Benefits of Sauna Usage

Photo by Solskin on PIxabay

I have previously alluded to the various health and longevity benefits of regular sauna sessions. This seems to have raised a few eyebrows, both from those that are sceptical, and those that want to know more. I was thinking this over this morning (during my post-workout sauna session). I thought it would be worth diving deeper into the purported benefits of sauna usage.

Whether sat in a traditional sauna, or a modern infrared sauna, at the simplest level a sauna session simply involves sitting down and sweating… a lot. Most people think of saunas in general terms, around detoxifying the body, or losing weight. But, what’s going on beneath the skin? There are wide ranging claims about what saunas can do for you.

This includes; slowing ageing, boosting your mitochondria, detoxifying your body, improved heart health and blood pressure, increased athletic performance, muscle growth and recovery, weight loss, reduced pain, inflammation, illness and disease, boosts to your immune system, optimised brain power, and mental states. These benefits sound pretty amazing, and all from sitting around in a sauna a few times per week. When something sounds too good to be true, it’s worth digging into the detail.

The primary benefits of the sauna are unsurprisingly derived from the hot conditions. Hyperthermic conditioning is the term for the changes that your body undergoes when exposed to heat “stress”. This is known as hormesis, the phenomenon whereby the body reaps benefits when exposed to low doses of a stressor, in this case heat. Building upon that foundation, here are the actual evidence backed benefits of sauna usage.

Slowing Ageing and Increasing Longevity

The Finns love a sauna session, and a 20 year study of over 2,000 Finnish men found that the more time they spent in the sauna each week, the less likely they were to die. 2 to 3 sessions a week decreased the chances of death from fatal cardiovascular and all-cause mortality events, by around 24%. Increasing to 4 to 7 sauna sessions per week boosts that figure to 40%[1].

Pretty amazing! But why is this? One theory is that the heat from the sauna causes your body to produce heat shock proteins (HSP), which have been implicated in increasing longevity[2]. They promote cellular autophagy (the repair and recycling of damaged cells), and also preventing future damage by supporting the maintenance of antioxidants such as glutathione[3].

Heat also activates the protein FOXO3 which has been found to play a major role in slowing ageing and living longer[4]. FOXO3 influences a wide array of other genes responsible for crucial cellular processes regulating stress resistance, metabolism, cell cycle arrest, and apoptosis (cell death)[5]. Essentially, the sauna proves to be an excellent method of providing the heat to trigger both HSP and FOXO3, helping you to maintain your body and live longer.

Boosting the Power of Your Cells

Mitochondria can be thought of as the batteries powering our cells, and as such they are vital for our health and longevity. We want plenty of big, powerful mitochondria keeping us super fit and healthy as we grow older. If your mitochondria are small and weak, then so are you! And this can speed up ageing and cause multiple diseases[6].

Once again, heat stress has been shown to have a positive impact on mitochondrial health[7], helping the body to produce more mitochondria, make your mitochondria bigger and stronger, recycle and repair existing mitochondria, and better protect your mitochondria from oxidative stress. All of this means a greater capacity for your body to generate energy, and remain fit, healthy, and functioning at optimal levels, whilst also once again slowing the ageing process.

Detoxifying and Cleansing the Body

In the modern post-industrial world we are all exposed to a large variety of potentially toxic heavy metals and chemicals[8]. Even the most health conscious individual will still have a wide range of toxins in their body. However, the sauna offers one of the best possible ways that we can manage the ongoing detoxification of our bodies.

You can probably guess that sweating plays a major role here. Sweating is the optimal method our body has for excreting toxins in the highest concentrations[9]. By simply sitting and sweating we are allowing our bodies to flush out a whole range of harmful toxins, including heavy metals such as arsenic, cadmium, lead, and mercury[10], as well as accumulated industrial chemicals.

In the modern world we live fairly sedate lifestyles in controlled climates to keep us comfortable. This means we need to make specific time to sit and sweat and detoxify our bodies. The heat can also boost the functioning of your autonomic nervous system (ANS), which actually increases your ability to sweat more. Thus the sauna creates a virtuous cycle, helping your body to detoxify and balance itself.

Improving Heart Health and Blood Pressure

Heart disease is the leading cause of death across the world. I already referenced the study that shows how multiple sauna sessions lower the risk of death. Specifically in relation to heart disease, 2 to 3 sessions a week reduced the risk of death from coronary heart disease (CHD) by 23%, and the risk of death from cardiovascular disease (CVD) by 27%. 4 to 7 sessions a weeks pretty much doubles those figures to 48% and 50% respectively. Another study showed similar results, with regular sauna usage showing a 58% reduction in the chance of dying from CVD[11].

In addition, even just using the sauna every few weeks has been shown to be able to help hypertensive people experience a drop in blood pressure that matches that delivered by medication[12]. Another study found that more regular sauna usage (again 4 to 7 times per week), could cut the risk of high blood pressure by up to 50%[13].

In the case of the heart and blood pressure, this could well be because heat from the sauna can improve blood flow, and the function of your nervous system and heart[14]. All of which keeps your blood flowing as it should, and your heart healthy, and functioning as it should. Again, some of these stats sound pretty astounding, but these studies are comprehensive and repeatedly showing the same results!

Improving Athletic Performance

And what about the rest of the body? Incredibly, just sitting in a sauna can actually increase athletic performance. One study on male long distance runners found that regular sauna bathing increased their run time to exhaustion by 32%[15]! These are the sort of results one might expect from performance enhancing drugs… not just from sitting in a sauna!

Again, a large part of this comes down to the impact of hyperthermic conditioning. Heat stress causes an increase and improvements in blood flow to the heart, and an increase in plasma and red blood cell volume. This helps your body transport oxygen faster and more efficiently[16]. Heat stress also ramps up your body’s thermoregulatory system, helping you to better regulate your body temperature[17]. This in turn leads to the potential for improved performance, and recovery and growth[18].

Increasing Muscle Growth and Recovery

Sauna usage can help increase the size of your muscles, reduce muscle breakdown or less, and help with muscle recovery. That’s a pretty incredible set of benefits. Time in the sauna has a huge impact on human growth hormone (HGH) levels. Spending two one hour sessions per day in a sauna, for seven days straight, was shown to increase HGH by between 2 to 5 times[19].

HGH activates an increase in insulin-like growth factor 1 (IGF1)[20], and increases insulin sensitivity[21]. These factors lead to an increase in the improved uptake of amino acids, increased protein synthesis and a decrease in protein breakdown, all of which are the building blocks for putting on and maintaining muscle mass. The previously mentioned reduction in oxidative stress (through sauna usage) also helps to minimise muscle breakdown and reduce inflammation. Both of which help with muscle maintenance and recovery[22].

Helping with Weight Loss

As well as helping you get (and stay) big and strong, sauna usage can also assist with weight loss. In one study participants engaging in regular sauna sessions lost almost 2 times more weight and nearly 5 times more body fat compared to the control group[23]. This is largely due to the fact that sauna usage can help to regulate the appetite[24], and the heat stress also increases metabolism and oxygen utilisation to similar levels as those shown during moderate exercise[25].

Fighting Pain and Inflammation

From headaches[26] to chronic pain[27], sauna usage has proven an effective treatment. A big part of how sauna bathing eliminates pain is the way in which it works on inflammation. Inflammation is a result of the body trying to heal itself. However, there are multiple environmental and behavioural factors that can excessive chronic inflammation.

Inflammation is the hidden, internal cause of almost all major diseases, and massively contributes to ageing and death. Reducing inflammation is a big key to optimising your health and longevity, and studies suggest that the sauna can help. The HSPs I mentioned earlier play a part, as they are anti-inflammatory proteins[28].

Additional studies do show that regular sauna usage reduces evidence of oxidative stress, which can often cause inflammation. In particular regular sauna goers have lower levels of C-reactive protein (CRP), which is a specific indicator of chronic inflammation[29]. So, heating ourselves up can actually reduce inflammation. And this is one of the best possible things we can do for ourselves in terms of optimising our health and longevity.

Beating Illness and Disease

Beyond pain and inflammation, sauna usage can also potentially help to fight a range of illness and disease ranging from Alzheimer’s and dementia, and respiratory disease, right through to cancer. As previously mentioned, sauna usage increases HSP and FOXO3 levels, which can play a key role in repairing misfolded proteins in the brain (a key component of many neurodegenerative diseases such as Alzheimer’s). One study has shown that regular sauna usage has the potential to reduce the risk of Alzheimer’s and dementia by over 65%[30]!

Moving south of the mind, sauna usage has also been proven to be highly effective at combatting lung and respiratory disease. Regular sauna usage can reduce the risk of respiratory disease by over 40%[31]. Sauna usage causes a hormetic response in the lungs which helps to decrease congestion and increase the operation and functioning of the lungs[32]. This in turn helps the lungs to fight off infection, and perform at optimal levels, reducing the risk and symptoms of illness and disease.

Finally, sauna usage may have a positive impact in helping to fight cancer, by causing apoptosis in tumour cells[33]. It is suggested that this could be because normal, healthy cells are capable of adapting to stress, whereas cancer cells cannot[34]. Again, FOXO3 can play a key role in the suppression of tumours[35]. Finally, tumour cells are far more at threat from heat due to reduced blood flow. And there are studies that the use of heat can improve the results of treating a variety of cancers, by up to as much as 50%[36].

Boosting Your Immune System

As well as fighting pain, inflammation and illness and disease, sauna usage can also help boost your immune system. Making you fitter and stronger and more resistant to disease in the first place, and more effective at fighting it off when it does arrive. Heat stress raises the body temperature, mimicking the effects of a fever, in turn giving your immune system a workout. In technical terms this may be due to the increase in HSPs, which stimulates immunity[37].

This helps to strengthen your immune system and prepare it for any illness and disease. For example, multiple studies have shown to reduce the occurrence of the common cold by up to as much as 50%[38]. These recent sections highlight many of the ways in which the sauna can help fight pain, inflammation, illness and disease, and also to boost your immune system. Furthermore, the evidence supporting these claims is compelling.

Optimising Your Brain Power

Moving from body to brain. The sauna boosts your brain power and health. It does this by increasing levels of brain-derived neurotrophic factor (BDNF). BDNF facilitates the growth of new brain cells, and helps to maintain existing ones, and it also enhances neuroplasticity (the formation of new neural connections that help with things like learning and memory)[39].

Boosting BDNF production is often linked to exercise, and whilst this is true, the effect is dramatically increased by combining exercise and sauna bathing[40]. This helps your brain stay healthy. Supporting this the sauna usage also appears to support increases in hormones like norepinephrine, and prolactin, which are very important for nerve growth and repair[41].

Beating Depression and Improving Your Mood

From body, to brain, now to mind. There are multiple ways in which sauna usage can also help fight depression and boost your mood. Reducing inflammation, promoting cellular autophagy play a role in making your body, and brain healthy and less susceptible to stress, which in turn helps with your mental states. Sauna bathing has also been shown to both release endorphins, and make you more sensitive to endorphins[42]. Ultimately this helps to put you in a better mood, and keep you there.

Further studies support this showing specifically how in multiple scenarios, heat therapy offers substantially better and longer lasting results in terms of reducing depression, and increasing personal interactions, stress relief and relaxation[43]. Effect which have been shown to persist for as long as 6 weeks[44], which beats the hell out of antidepressant drugs! In fact, the sauna is an extremely powerful therapeutic tool.

So, there you have it. Honestly, I’ve always just enjoyed a relaxing sauna session after a workout. And whilst I’ve become more aware of the evidence backed benefits over the years, once I got deep into research for this article, even I was quite surprised by the number of wide ranging benefits of sauna usage. Pretty amazing! And in many cases the supporting evidence is not tenuous, but highly compelling.

I do believe that the sum is greater than the parts, and obviously by taking regular sauna sessions you will accumulate a wide range of overlapping benefits. And all just from sitting in a sauna and sweating, which overall is a pleasant experience for most people. And typically it is very complementary when coupled with traditional exercise and treatments.

Therefore, I would of course finish with a reminder, that whilst the sauna can offer amazing benefits, you should still consult with your physician for any specific ailments, and you should not believe that the sauna can cure all your ills! However, it does offer a lot of benefits and I hope this article gives you cause to dig deeper and explore the powerful benefits of regular sauna bathing.

Writing this up has got me craving a sauna big time! So, I’ll be heading off to the gym for a session in due course. I’ll follow that up with a good session in the cold plunge pool. That may well be the focus of a future write up. We’ve talked about the benefits of heat, and I’ll take a look at the benefits of cold therapy, and how the benefits of both hot and cold therapy multiply when they are combined.