Saunas are hot these days.
This practice has seen a significant surge in popularity recently, with many constructing their own saunas, purchasing personal units, or making regular use of facilities at health clubs.
As an advocate for holistic health approaches, Saunas and their variations can be pretty easily accessible.
For some, it’s a $10,000 backyard sauna, but even if your options are limited to wrapping a heated blanket around your legs after a long day of sitting, saunas can be something that everyone uses.
As we delve deeper into this topic, you’ll gain a comprehensive understanding of why such practices could be beneficial and learn about the wide-ranging health benefits they offer.
In our discussion, we’ll cover how sauna therapy works on a physiological level.
There will be some discussion on how it impacts whole-body glucose metabolism, a crucial factor in overall health and disease prevention.
We’ll explore its role in improving microvascular circulation, which is particularly beneficial for those struggling with poor circulation or varicose veins.
Additionally, we’ll examine how sauna use can enhance vital capacity or lung function, and lastly, how to use it yourself.
How it Works
Let’s begin by examining the concept of heat as medicine, and more specifically, sauna as a therapeutic tool.
It’s worth noting that in many contexts, you can substitute “sauna” with other forms of heat therapy such as an infrared blanket, infrared sauna, or even a hot tub.
The key is consistent exposure to therapeutic heat, usually above 120-190° Fahrenheit (50-60° C).
When your body is exposed to heat, it initiates a natural mechanism to divert heat from the core to the periphery.
This process increases blood flow to the peripheral areas of your body, including your skin and extremities.
This physiological response is fascinating because it directs a significant amount of blood to your muscles – a phenomenon that doesn’t typically occur for people who don’t exercise regularly (so essentially, you mimic the blood flow of exercise without actually exercising).
This heat-induced physiological response triggers the production of nitric oxide, leading to vasodilation.
Your arteries have the capacity to dilate or constrict, and when you start to get hot, natural mechanisms trigger adaptations.
The smooth muscles in your microvasculature and blood vessels effectively get a workout. Many people miss out on this beneficial process if they don’t engage in regular physical exercise, which is why those who lead sedentary lifestyles should consider sauna use as a way to give their cardiovascular system a much-needed workout.
An intriguing aspect of heat therapy that I found in my research is the “hunting response,” which comes into play when contrast therapy is introduced.
Here’s how it works: When you’re hot and your blood vessels are dilated from sauna use, and then you suddenly expose yourself to cold (like a cold shower, ocean, or lake), your blood vessels rapidly constrict and blood is sent back to the core of your body.
This isn’t a one-time occurrence – it happens cyclically over a period of about 90 minutes.
This combination of heat and cold thermogenesis is particularly exciting for those with circulatory issues such as peripheral edema, peripheral vascular disease, poor blood circulation, cellulite, or varicose veins.
The alternating hot and cold helps return stagnant fluids to circulation and may help reduce inflammation.
Even if you just experience cold hands and then warm them up, there will be a cycle of increased blood flow and muscular contractions over the course of 90 minutes without you even being consciously aware of it.
So a deeper look at the data: A systematic review of the clinical effects of regular dry sauna bathing provides more insight into the mechanisms of action, and it goes beyond vasodilation.
Sauna bathing increases cardiac output, reduces peripheral vascular resistance, and induces other physiological changes in cardiovascular parameters.
These include decreased systolic and diastolic blood pressure, increased heart rate variability, improved cardiac functional markers, and enhanced blood flow-mediated arterial and vascular dilation.
There is also a hormonal and metabolic effect that comes as a result of using a sauna.
Sauna use reduces levels of epinephrine and norepinephrine, which are markers of the body’s stress response.
It increases levels of nitric oxide metabolites, which play a crucial role in vascular health.
Regular sauna use has also been associated with decreases in total and LDL cholesterol levels, improvements in growth hormone levels, and decreases in fasting glucose.
These metabolic effects could have far-reaching implications for overall health and disease prevention.
The Data and Benefits
And the benefits come as a result of these physiological changes.
Let’s get right into the facts.
Long-term prospective studies following large cohorts of individuals have yielded compelling results.
These studies have demonstrated that both the frequency and duration of sauna therapy strongly correlate with reductions in all-cause mortality, cardiovascular mortality, and sudden cardiac death.
To put this into perspective, heart disease claimed a staggering 690,000 lives in 2020 alone, and is one of the leading causes of death in the United States and worldwide.
If just sitting in a hot room lowers this risk, you better believe I’m doing that.
The Heart
There are various scientific methods to measure these effects, such as flow-mediated dilation tests or arterial stiffness assessments.
The key benefit here is improved endothelial health.
The endothelium, composed of small cells that line your blood vessels, can become dysfunctional over time or due to various health conditions, like chronically high blood pressure or high cholesterol.
This state, known as endothelial dysfunction, is often a precursor to further cardiovascular complications, including erectile dysfunction, stroke, or heart attacks.
By exposing yourself to heat in a sauna, you’re essentially exercising your endothelium – the functional unit of your cardiovascular system.
This process also promotes angiogenesis, or the formation of new blood vessels, in your skeletal muscle.
As blood is directed to your skeletal muscles during heat exposure, they respond by creating new blood vessels.
This angiogenesis is highly beneficial for muscle tissue and significantly improves microvascular circulation throughout the body.
Fluid Flow
While it’s somewhat speculative at this point, I believe there’s likely some improvement in lymphatic return as well during sauna use.
The lymphatic system, crucial for immune function and fluid balance in the body, may benefit from the increased blood flow and temperature changes experienced during sauna therapy.
There is actually a trend going around now where people do a “lymphatic massage” on their face to reduce swelling and bloating, so there is another thing that saunas can mimic.
Immune System
The immune system also reaps significant benefits from heat exposure.
Heat activates special proteins called heat shock proteins, which, along with short-term increases in immune signaling molecules called interleukins, favorably impact the immune system and various signaling pathways within the body.
These heat-induced changes also help reduce oxidative stress by activating the body’s natural antioxidant response elements.
Various types of immune system cells are activated or increased during sauna use.
These include neutrophils, which are first responders to infection; monocytes and macrophages, which engulf and destroy pathogens; and T lymphocytes, which play a central role in cell-mediated immunity.
Moreover, the phagocytic capacity of these cells – their ability to engulf and destroy harmful particles – is enhanced.
Given the current global focus on immune health, sauna therapy could be considered as a valuable adjunctive lifestyle treatment to boost overall immune function.
Brain Function
Regular sauna use can also significantly reduce the risk of dementia and Alzheimer’s disease.
Perhaps most striking is the observed 65-66% reduction in the risk of dementia and Alzheimer’s disease among regular sauna users.
Studies have shown significant reductions in the risk of dementia and Alzheimer’s disease in cohorts followed for 26 years in Finland.
These findings suggest that sauna use could play a role in maintaining cognitive health as we age.
Personally, I’ve noticed improvements in my memory function after sauna sessions.
This could be due to improved circulation and potential angiogenesis in the brain’s microvasculature, enhancing oxygen and nutrient delivery to brain cells.
Research has also observed changes in levels of brain-derived natriuretic peptide (BNP) during sauna use.
This peptide is involved in osmotic regulation in the blood, and high levels are typically linked to elevated blood pressure.
Interestingly, one of the main benefits of sauna use is its ability to reduce high blood pressure.
Several studies involving people with elevated blood pressure wearing 24-hour monitors have shown an almost immediate reduction in blood pressure following sauna use.
This effect could have far-reaching implications for cardiovascular health and disease prevention.
Bones
Now, let’s delve into the fascinating effects of sauna use on bone health.
When you expose your body to heat, more blood is directed to your bones.
In response to this increased blood flow, your bones release stem cells.
This process improves red bone marrow production and enhances overall bone marrow circulation.
It’s an exciting benefit because, outside of weight-bearing exercise, there aren’t many activities that stimulate increased circulation in the bones.
This could have implications for maintaining bone density as we age and potentially in the treatment or prevention of conditions like osteoporosis.
Glucose Regulation
Several studies focusing on diabetic patients have shown improved glucose clearance in the legs after simply warming them up.
This is particularly significant because we know that sedentary behavior can induce insulin resistance in leg muscles.
The improved glucose uptake observed with heat therapy could potentially complement other treatments for type 2 diabetes and metabolic syndrome.
Summer Heat Training
Given that I’m making this post in the summer, you might be wondering why you should expose yourself to MORE heat in the summer.
By incorporating strategic heat exposure into your routine, you can increase your blood plasma volume, improving your body’s ability to cool itself while maintaining oxygen delivery to muscles.
These adaptations can benefit your performance even in cooler conditions.
It’s kind of like sprinting with a parachute – it might slow you down a little bit but you will adapt better in the long run.
Heat Training Strategies:
- Hot Runs: The most effective method is running for 30-60 minutes at an easy to moderate pace in hot conditions. Aim for 8-14 sessions over several weeks. If outdoor conditions aren’t warm enough, use a treadmill in a heated room or wear extra layers to simulate heat stress.
- Sauna Sessions: Post-run sauna sessions can boost plasma volume and endurance. Start with 5-10 minutes at 175°F and gradually increase duration and temperature. Even just four 30-minute sessions at 189°F can increase plasma volume significantly.
- Short-Term Benefits: If time is limited, even 3-7 heat adaptation runs can produce a worthwhile 3.5% increase in plasma volume, offering noticeable performance improvements.
- Hydration Strategy: During heat training, drink according to thirst. Mild dehydration may actually trigger plasma expansion. Aim to lose no more than 2% of your body weight, and rehydrate immediately after your session.
- Balancing Your Training: Incorporate heat training gradually into your routine. Start with 1-2 sessions per week and increase as your body adapts. Continue your regular, cooler workouts to maintain speed and intensity.
Remember, heat training adds stress to your body.
Listen to your body and balance it carefully with your regular training.
Allow for adequate recovery between heat sessions.
With consistent application, you can turn summer heat from a training obstacle into a performance-enhancing tool, potentially seeing benefits that carry over into cooler seasons as well.
How to Use Saunas
When it comes to frequency and duration of sauna use, a general guideline is to stay in as long as you’re comfortable.
However, it’s crucial to listen to your body and consider your overall stress levels.
Sauna therapy, while beneficial, is a physiological stressor.
If you’re already psychologically or mentally stressed, or if you’ve had a particularly intense workout or poor sleep, you might want to take it easy in the sauna or even skip a session.
On days when you’re feeling energetic and well-rested, you might choose to do multiple rounds at higher temperatures.
The key is to use your intuition and adjust based on how you’re feeling.
Remember, the goal is to reap the health benefits without overstraining your body.
The general rule of thumb is 2-5 sessions per week for 10-40 minutes at a time.
Obviously, start lower and build up your tolerance.
As for the type of sauna, whether it’s an infrared sauna or a classic Finnish sauna, the best one is the one you can afford and will use consistently.
If you don’t have the time or inclination to build a fire for a traditional Finnish sauna, an infrared sauna that you can turn on with the push of a button might be more suitable for your lifestyle, and many modern health clubs have access to these.
There are some differences between infrared and traditional saunas that are worth noting.
Infrared saunas provide a dry heat that penetrates deeper into the body, while traditional saunas offer a wet heat when water is poured over hot rocks, creating steam.
Both have their unique benefits, and infrared saunas (known as “waon therapy” in Japan) have been the subject of much research, particularly in the realm of cardiovascular health.
If you don’t have access to a full sauna, you can still benefit from using a sauna blanket or other portable heat therapy devices.
The key is to find a method that works for you and that you’ll use regularly.
Consistency is crucial in reaping the long-term health benefits of heat therapy.
For those seeking convenient at-home sauna therapy, the SaunaBox is a portable option I personally use.
It offers the benefits of sauna sessions without requiring permanent installation or significant space.
As someone who values regular sauna use, I’ve found the SaunaBox to be a game-changer for consistency.
Its portability allows for flexible use at home or while traveling.
While it may not replicate a traditional sauna experience exactly, it still provides key benefits like heat exposure, recovery, and relaxation.
Remember, the most important factor in sauna therapy is finding a solution that fits your lifestyle and encourages regular use.
The SaunaBox or similar portable options can help ensure consistent heat exposure, making it easier to reap the long-term health benefits of sauna therapy.
If you’d like to grab one, use my code “POULOS10” for a bit of a discount as well.
In conclusion, the science behind sauna use and heat therapy is compelling and multifaceted.
The benefits to the microvascular system, blood composition, heart function, bone health, lung capacity, and beyond are extensive and well-documented.
Whether you’re looking to improve your cardiovascular health, boost your immune system, enhance your lung capacity, maintain cognitive function, or simply relax and de-stress, regular sauna use could be a valuable addition to your health and wellness routine.
Sources:
https://www.mayoclinicproceedings.org/article/S0025-6196(23)00008-3/fulltext
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2130724
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All the best,
Dr. Christian