Taking a regular sauna can be extremely good for relieving and preventing common acute and chronic conditions, perhaps by supplementing or simulating exercise.
The health benefits of using a sauna are a “hot topic” in health research. The Fins, other Scandinavians and northern Europeans have been proclaiming their health benefits for generations. Anecdotal claims of health benefits of traditional practices are rarely backed up by medical evidence, but recent studies have shown that taking a regular sauna can be extremely good for relieving and preventing common acute and chronic conditions.
Sauna is passive heat therapy which originates from Finland and is mostly associated with Nordic countries. It is used mainly for pleasure and relaxation and involves spending short periods of time (usually five to 20 minutes) in temperatures of 80°C to 100°C, interspersed with moments of cooling-off in a pool or shower.
Although there are other forms of heat therapy or hyperthermic conditioning, the traditional Finnish sauna is the most examined to date, with the most empirical evidence.
Hyperthermic conditioning is the practice of intentionally acclimatising to heat, either without or alongside exercise. Other forms of heat therapy including hot baths, steam showers, Turkish baths, infrared saunas, Waon therapy and hot yoga. These modalities likely create as good a quality of heat stress as sauna bathing, depending on intensity.
Rhonda Patrick, PhD – who worked with Dr Bruce Ames, the 23rd most-cited scientist in all fields between 1973 and 1984 – conducts clinical trials, performs ageing research at Salk Institute for Biological Studies, and at St. Jude Children’s Research Hospital, where she focused on cancer, mitochondrial metabolism, and apoptosis. She explained in a 2014 article, ‘Are Saunas the Next Big Performance-Enhancing “Drug”?’, that:
…increasing your core temperature for short bursts [hyperthermic conditioning] is not only healthful, but it can also dramatically improve performance. This is true whether it’s done in conjunction with your existing workout or as an entirely separate activity… heat acclimation through sauna use (and likely any other non-aerobic activity that increases core body temperature) can promote physiological adaptations that result in increased endurance, easier acquisition of muscle mass, and a general increased capacity for stress tolerance…. [there are] positive effects of heat acclimation on the brain, including the growth of new brain cells, improvement in focus, learning and memory, and ameliorating depression and anxiety. In addition… modulation of core temperature might even be largely responsible for “runner’s high” via an interaction between the dynorphin/beta-endorphin opioid systems
Dr Rhonda Patrick
In the video below, Dr Patrick explains several of the performance benefits plus the biochemistry and physiology behind these benefits. They include:
- Improved cardiovascular mechanisms and lower heart rate
This links to an important review article that covers some of the benefits of sauna use including the cardiovascular advantages and hormonal alterations like a boost in growth hormone levels. It also covers the risks of alcohol use before or during the sauna - Lower core body temperature during workload
- Higher sweat rate and sweat sensitivity as a function of increased thermoregulatory control.
- Increased blood flow to skeletal muscle (known as muscle perfusion) and other tissues.
- Reduced rate of glycogen depletion due to improved muscle perfusion
This link demonstrates that glycogen degradation and glucose uptake is reduced in runners after heat acclimation. - Increased red blood cell count (likely via erythropoietin) and efficiency of oxygen transport to muscles.
This link demonstrates the effect of preconditioning the body to heat stress by using a sauna for at least 30 min directly after a training session.
Dr Patrick also had some anecdotal data. She would sit in the sauna for up to 60 mins, experiencing extreme physical discomfort, about 4-5 times per week and substantially (I know this is n=1 data) increased her running personal records.
Sauna Use as a Supplement or Substitute for Cardiovascular Exercise:
Not only can sauna increase the effects of exercise but it can also act as a mimetic, or mimic exercise. I guess you can think of it being like doing extra exercise when done in heat, or instead of exercise when you skip the workout.
The positive benefits of the sauna on heart health, with or without actual exercise, occur because both sauna and exercise cause similar physiological changes. A majority of blood is redistributed from the core to the skin to allow sweating. In a sauna, heart rate elevates to up to 150 beats per minute which correspond to moderate-intensity physical exercise.
Cardiac output – the amount of blood excreted from the heart to match the body’s need for oxygen – goes up by sixty to seventy per cent. Straight after using a sauna, blood pressure and resting heart rate are below baseline, which replicates physical activity.
Research has shown that 30 minutes in the sauna after a workout, twice per week for three weeks, increased the time to run until exhaustion that it took for study participants to run until exhaustion by 32% compared to baseline.
Sauna Use as a Potential Tool for Longevity and Healthspan:
In a 2015 study published in JAMA Internal Medicine, researchers from the University of Eastern Finland recorded the sauna bathing habits of 2,300 middle-aged men and compared how often they used a sauna with cardiovascular-related deaths and all-cause mortality including cancer over the course of more than two decades.
They found that those who used saunas regularly suffered from dramatically fewer deaths from heart disease or stroke, with a reduction of over one quarter for those who used the sauna two to three sessions per week and by half for those who sauna bathed four to seven out of seven days compared to those who only used the sauna once per week
Loads of research has shown that sauna bathing four to seven times per week at 174°F for 20 minutes is associated with 50% the risk for fatal heart disease or stroke, a 40% decrease in sudden cardiac death risk, and almost halves the risk for hypertension.
A single session of sauna can enhance heart rate variability, decreased blood pressure, and increase arterial compliance.
Scientists are not certain how saunas reduce heart disease, but it is likely predominant;y through the effects on blood pressure outlined above. High blood pressure is one of the condition’s major risk factors.
Heat stress from the sauna increases plasma volume and blood flow to the heart, known as stroke volume, which means a reduction in cardiovascular strain because your heart has to do less work for each beat that it does when pumping oxygen-rich blood to your body organs and brain. This is an improvement in cardiovascular function and subsequently reduces the risk of heart disease.
Heart rate increases from 100 to 150 beats per minute mimic moderate-intensity physical exercise that is well known to improve cardiovascular health and a boost of endurance.
Thinking of mild adaptations to heat exposure as a substitute or supplement for cardiovascular exercise then the longevity effects begin to make sense.
As well as decreasing risk factors for cardiovascular-related death, sauna use may have benefits for general longevity. Sauna use 2-3 times per week is correlated with nearly 1/4 lower risk for all-cause mortality. This improves to 40% with 4-7 times per week sauna usage.
What does ‘all-cause mortality’ mean? Unfortunately, it does not mean that sauna bathing four to seven times per week makes 4 in 10 people immortal. It means that the persons studied had 40% fewer deaths than similar (body mass, serum cholesterol, blood pressure, smoking amount, alcohol consumption, type 2 diabetes, physical activity, socioeconomic status and age) subjects who did not undergo these sauna conditions, and that is a decrease in deaths was not solely due to heart disease, but a more general reduction.
Sauna Bathing and Neurodegenerative Disease:
Sauna use is correlated with a lowered risk of neurodegenerative disease like Alzheimer’s. People who used the sauna 2-3 times per week were found to have a fifth lower risk of Alzheimer’s disease. This improved to a 60% reduction with 4-7 times per week sauna usage when compared to men only used the sauna once per week.
The same research group from the University of Eastern Finland who did the cardiovascular death risk study in 2015 conducted a follow-up study the following year and found frequent sauna usage was associated with a dramatically decreased risk of dementia.
They found that men that used the sauna twice to three times per week had at least a 1/5 lower risk of dementia and Alzheimer’s disease compared to men that used the sauna a single time on average each week.
Participants that used the sauna four to seven days per week had around a 65% lower risk of dementia and Alzheimer’s disease compared to the single use participants. As before, this was after controlling for age, alcohol consumption, BMI, systolic blood pressure, smoking habits, type 2 diabetes, previous heart problems, resting heart rate and serum LDL cholesterol.
How Does Sauna Improve Health and Longevity?
There are two molecular pathways that likely hold the mechanisms increases in longevity: heat-shock proteins made in the cells in response to heat stressors and the FOXO3 pathway.
Heat Shock Proteins:
Much of the improvements in health and lifespan of sauna bathing likely has to do with an elevation in ‘heat shock proteins’ that are activated. Heat shock proteins have been associated with anti-aging where upregulation has been demonstrated simpler organisms like flies and worms to extend their longevity by nearly 15%.
In addition, polymorphisms that elevate heat shock protein production in people have been demonstrated to have a correlation with improved lifespan.
Heat shock proteins assist all other proteins to maintain their correct 3-dimensional shape in the cell, which is essential for the protein to be able to retain its function. If any of the multitudes of reactions that are present break the building blocks of that protein, e.g. denaturing it, then it will be unable to fulfil its purpose and will short the half-life of the protein.
Damaging byproducts, such as free-radicals, get produced from normal metabolism and immunity. These destructive molecules, which are made at a low level daily even in the best of circumstances but are worsened by poor lifestyle decisions, disrupt the structure of the protein proteins.
Additionally, once a protein’s structure is disrupted, it can then misfold, preventing degradation and leads to the build-up toxic protein derivatives that can also damage other cells.
Read more…
There is No Such Thing As Healthy Aging
Degenerative protein segments – the aggregates that heat shock proteins especially aids in the prevention of the accumulation – are believed to be causal in neurodegenerative diseases such as Alzheimer’s, Parkinson’s and Huntington’s diseases. It has been proven that normal mice that have been genetically altered to accumulate amyloid-beta plaques (like Alzheimer’s) begin to display brain pathology that simulates Alzheimer’s but if you alter the same mice to over-produce a populous heat shock proteins, HSP70, the severity of the condition is reduced, including decreasing the resultant loss of brain white matter (neurons and synapses).
This suggests support for the role pf heat shock proteins in the reduction in Alzheimer’s and dementia found by the Finnish group.
The aerobic endurance and cardiovascular improvements were seen with sauna bathing may play a role in the reduction of the incidence of neurodegenerative conditions such as dementia.
VO2 max, the body’s maximum volume of oxygen delivered to the muscles and organs during exercises, has a strong correlation with mental capacity in older adults. This could have a lot to do with brain perfusion and/or waste product clearance including amyloid-beta plaques.
FOXO3 Pathway:
The other molecular cascade that may go someway to explaining some of the association between a type of lifespan benefits of sauna use is the FOXO3 pathway.
As we age, our FOXO3 activation tends to lower. FOXO3 is a master regulator that plays a role in immunity, autophagy, stem cell activation, metabolism, DNA repair and natural antioxidant production.
Some experiments have found that part of the cell’s normal reaction to heat stress is an activation of this pathway. FOXO3 is one of the major ageing genes for which normal genetic variation found in people has been shown to be involved in lifespan.
People with a polymorphism that produces more than the usual FOXO3 have up to 2.7 times a chance of surviving to be an over 100 years old and mice can live almost a third longer than normal mice.
So there you have it! That is why sauna use is good for you and by what means it achieves these benefits for cardiovascular health, neurodegenerative diseases and lifespan.
If you want to know how sauna use helps with resistance training or the best dosing for sauna, then click on the link at the bottom of the page.
Enjoy!
Scott
Dr Patricks provides some more in-depth research, with citations, where you can learn more about sauna – including heat source; duration; humidity; temperature; physiological responses; molecular mechanisms including heat shock proteins; effects on specific diseases/pathologies including inflammation and mental health; hormonal and metabolic function; fitness and performance; detoxification; health concerns and special population like pregnancy and children; and hydration – here.
Studies on the Effects and Benefits of Sauna Bathing:
- Sauna use associated with reduced risk of cardiac, all-cause mortality (PubMed)
- Frequent sauna bathing may protect men against dementia, Finnish study suggests (PubMed)
- Frequent sauna bathing reduces risk of stroke (PubMed)
- Frequent sauna bathing keeps blood pressure in check (PubMed)
- Scientists uncover why sauna bathing is good for your health
- Sauna bathing and systemic inflammation (scholarly).
- Heat stress increases lifespan in flies