Health Benefits of Heat Therapy
Article by Stefan Burns - Updated December 2021. Join the Wild Free Organic email newsletter!
Everyone knows the huge health benefits that come from exercising daily, eating vegetables, and sleeping eight hours every night. Other wellness practices that offer tremendous health benefits, like heat therapy, are lesser known. Enjoying the heat of a sauna, steam room, or hot bath has wide ranging health benefits such as reducing inflammation, cardiovascular improvements, and pain reduction.
A sauna is a room designed to stay at a high temperature in order to cause physiological effects. Regular saunas operate using a central heat source and usually range in temperature from 167–212 °F (75-100 °C), and have nearly zero humidity in order to not scald the skin. Steam rooms on the other hand have a humidity nearly at 100%, but are kept cooler at 104 °F (40 °C) in order to not scald the skin from the water vapor. Infrared saunas use infrared light to heat up the body from the inside out. While in a sauna, steam room, or infrared sauna, your body temperature will rise to 100 °F (38 °C) and you’ll begin to perspire in order to stabilize your body temperature from rising any further.
Saunas previously could only be found at spas or high-end health facilities but are now a common component of many gyms. Saunas are also available for purchase commercially though they are fairly expensive. Accessing and using a sauna has never been easier, and below are five incredible reasons why you should use a sauna regularly.
Heat Therapy Increases Longevity
Consistent sauna usage has been shown to increase longevity and improve subjective measures of well-being.
When you place your body into a sufficiently heated environment, heat shock proteins (HSP) throughout the body are activated.
In the presence of heat stress, these heat shock proteins (HSP) help protect the body by scavenging free radicals (unstable atoms that can damage cells) and also by supporting cellular antioxidant capacity.
HSPs also repair damaged proteins, helping them return to their proper structure and function. Structurally intact proteins are critical for maintaining normal functioning cellular mechanisms.
Using a sauna consistently assists the body to function smoothly on a cellular level. The stresses of daily life create cellular clutter, and heat therapy is one easy way to help clean it all up.
Brief heat exposure for yeast, flies, and worms increases their lifespan by up to 15% (1, 2, 3, 4). The triggering of the HSPs was directly shown to be responsibly for a 15% lifespan increase in these simple organisms.
To track longevity increases in humans who consistently use the sauna is more difficult than it is for simple organisms, but a few human studies have been done that have made some incredible findings:
A 20+ year study followed 2315 men from Finland 40-60 years old and found that sauna usage 4-7 times a week for sessions >20 mins on average experienced a 40% reduction in all cause mortality, aka death from anything (5). Factor out freak-accidents like car crashes and that 40% value is actually higher!
Additionally, the same study also found that sauna usage 4-7 times a week for sessions >20 minutes had a 48% lower risk of heart attack or fatal heart disease over those that used the sauna just once a week (already a healthy habit) (5).
The research on heat therapy is compelling, and it’s also backed up by thousands of years of anecdotal wisdom linking sauna usage and increased longevity.
Heat Therapy Improves Well-Being
Using the sauna will temporarily improve your well-being, and consistent use will semi-permanently improve your everyday well-being. These well-being improvements come from improved sleep and beneficial neurological changes.
Sauna usage has been shown to reliability increase sleep among people that use them regularly. One study had police officers, a very high stress job, use the sauna for four weeks. After one month, the officers boosted their sleep from 5.8 hours per night to 7.6 hours per night post-intervention (6). That’s a 30% increase in sleep quantity! Depending on your body, experts recommend 7-9 hours of sleep per night for adults. The secret to increasing your beneficial sleep comes from the release of endorphins.
After using the sauna, the body releases a steady stream of endorphins that lasts for several hours (7, 8, 9). Endorphins are opioids produced endogenously by the body, well known for their ability to ease pain, promote relaxation, and induce sleep. During the day, pursuing activities that release endorphins (exercise, sauna, meditation, sex) is a great way to prime yourself to fall asleep quickly and to experience improved sleep quality.
Sauna usage can also help manage depression. In a study with cancer patients, the patients who experienced whole body heat therapy (from a radiant heater) were markedly less depressed, angry, and tense for 72 hours post-treatment compared to pre-treatment (10).
Using the sauna is an acutely stressful event for the body, so as the heat stress builds up the body releases dynorphin, an opioid which gives you feelings of dysphoria, the opposite of euphoria. To counter the short term release of dynorphin, the body rewards the sauna user by increasing the production and sensitivity of beta-endorphin receptors, changes which are semi-permanent. Having a greater quantity of more sensitive beta-endorphin receptors means activities that do release endorphins become even more pleasurable.
Heat Therapy Increases Metabolism
With calorie over-consumption and obesity a major health epidemic worldwide, any wellness endeavor that can burn calories and kill fat cells is something worth experimenting with. And heat therapy does exactly that. Using Sauna usage results in the decrease of systolic and diastolic blood pressure as well as arterial stiffness. Meanwhile, sauna usage will increase heart rate to a level similar to mild cardiovascular exercise (11). Over a period of 30 minutes using the sauna can burn anywhere from 100 to 200 calories depending on your height, weight, and temperature. And unlike cardio, you won’t be tempted to replenish yourself by reaching for food anytime soon; using a sauna isn’t a hunger promoting activity.
Compared to control, 38 obese patients using heat therapy consistently over two weeks saw a significant drop in body-weight with both groups eating 1800 calories per day (12). But it gets even better. Burn fat, and keep it off! When exposed to heat stress, fat cells are injured and undergo cellular apoptosis (cellular death), while other nearby tissues are like the skin and muscle are more resilient (13).
While fat cells can increase or decrease in volume in response to changing levels of calorie consumption, it is very difficult to reduce the number of fat cells. The more fat cells you have, the more fat storage potential you have, which in normal context isn’t desirable. Reducing your number of fat cells through sauna usage is a great way to lose body fat and keep it off, permanently.
Also important for proper weight control and nutrient partitioning is insulin sensitivity. Sauna usage has been shown to decrease blood sugar levels and improve insulin sensitivity over a short time frame (14), and with consistent usage these results become semi-permanent improvements. With improved insulin sensitivity you gain greater lifestyle and caloric flexibility.
Heat Therapy Improves Cognition
For those who use the sauna 4+ times a week, it has been shown that they have a 65% reduced risk of developing Alzheimer’s Disease or other forms of dementia (5). When proteins unravel, they tend to clump together, forming protein plaques. It is the protein beta-amyloid which disassembles and clumps in the brain that causes Alzheimer’s disease. Heat shock proteins (HSPs), the very proteins released during heat stress help to repair damaged proteins. By using the sauna consistently, you’re releasing streams of HSPs which flood your bodily tissues and repair damaged proteins they encounter.
Another important factor for brain health is the hormone BDNF (brain-derived neurotrophic factor). BDNF is important in the formation of long term memories through its influence on brain plasticity. BDNF has been shown to reliably increase during running, understood partly to be an effect from the increased body temperature (15) that is generated from the cardiovascular activity. Similar effects are expected with sauna usage.
Memory formation and recall is of the utmost importance for retaining a sharp mind, and there are many neurotransmitters which are responsible for memory creation. Norepinephrine is a neurotransmitter that is released during stressful moments, helping to focus, strengthen, and store new memories through its effect on brain plasticity (16). Sauna usage can increase norepinephrine levels 310% over baseline (17)! Heat exposure is an acute stressor, so the release of norepinephrine during and after sauna usage makes sense. Have something you particularly need to study or remember? Be sure to use the sauna to relax afterwards!
Heat Therapy Builds Muscle
Building muscle, a desirable goal for many, ultimately boils down to the interplay of muscle protein synthesis (building muscle) and muscle degradation (losing muscle). If your muscle protein synthesis is higher than muscle degradation, then you’ll build muscle. If muscle degradation is higher than muscle protein synthesis, no matter their relative levels, then muscle will be lost. When the two are in balance then muscle is maintained.
Sauna usage has been shown to have beneficial effects for building muscle, boosting muscle protein synthesis and decreasing muscle degradation.
Sauna usage increases muscle protein synthesis
One of the most fascinating effects of the sauna is the tremendous surge of growth hormone (GH) that it causes (18). Growth hormone is a vital bodily hormone responsible for maintaining healthy tissues, joints, skin, and hair. Downstream of GH is IGF-1 (insulin-like growth factor 1), which is synthesized in response to growth hormone. IGF-1 is thought to be the main driver behind many of the anabolic effects of GH. IGF-1 activates the mTOR (a type of protein enzyme) pathway, which triggers muscle protein synthesis, and IGF-1 inhibits activation of FOXO proteins, consequently inhibiting protein degradation (19). Beneficial GH releases of 500% over baseline has been observed with normal sauna usage (17), such as two 15-minute dry sauna sessions at 212°F (100°C)! And this scales, with longer more frequent sauna sessions increasing growth hormone levels 1000+% over baseline (20).
And as mentioned earlier, improved insulin sensitivity brought on by sauna usage improves nutrient partitioning, shuttling nutrient towards muscular tissue instead of fat mass.
Sauna usage helps with recovery and reduces muscle degradation
Heat shock proteins (HSPs), due to their cellular cleanup roles, also help to prevent or mitigate oxidative stress by maintaining optimal glutathione levels (a naturally produced anti-oxidant) and through the scavenging of free radicals. When HSPs repair damaged proteins, this applies to damaged proteins found in damaged muscle fibers after injury or exercise.
When not in use, a muscle atrophies, and heat therapy using animals at 105.8°F (41°C) was shown to be dose dependent in reducing hindlimb muscle atrophy, with the 60 minute group stopping muscular atrophy by 32% compared to 20% for the 20 minute group (21). After atrophy occurs, muscle regrowth must occur to return to optimal health. If starting to exercise for the first time again in a while, this muscular reloading phase is particularly stressful and is responsible for a lot of oxidative stress throughout the body. The powerful abilities of heat shock proteins again come to the rescue, with heat therapy increasing muscle regrowth compared to control during a muscular reloading phase (22).
Heat Therapy is Great for Health
The sauna is a powerful wellness powerful that can be used to dramatically improve health, well-being, physiology, and more. These beneficial increases in longevity, increased muscle mass, reduced body fat, improved mental clarity, and improved well-being are mainly due to the release of heat shock proteins from the heat stress and the release of restorative growth hormone afterwards. Acute stressors such as exercise and heat therapy lead to improved health outcomes, whereas chronic stressors lead to disease. Heat therapy, being a wholly unique form of acute stressor, pairs synergistically with exercise in promoting abundant wellness.
Sauna usage is inherently different than exercise though because it is a very low energy activity. During the sauna you can stretch to improve your flexibility, practice breathing exercises, or meditate. One of the most important aspects is to practice mindfulness while using the sauna. Leave the cell phone outside and use the sauna with focus and intention.
As more research is done on sauna usage, I expect the popularity of heat therapy to increase. Maybe sauna usage will be just as popular as exercise one day!
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