Benefits of sauna use and the science behind it
Benefits of sauna use go beyond the relaxing and quite heavenly experience that you get from a 10 minute post workout sweat session. Sauna and steam rooms have a decent amount of research behind them. Recently Ironsnack took a trip out to Vegas for a week of pleasure. Aside from putting on some good weight through daily full body workouts and delicious buffets we spent a good deal of time at the spa, where we discovered the sauna. Jacob and I found it to be the perfect post workout start to the day. As a doctor I have been very curious about the effects the sauna has on the body. So here is what I found.
Sauna bathing is essentially sitting or lying in a hot room and the environment can be dry or wet. Wet saunas have temperatures of around 40 degrees Celsius compared to dry saunas but often can feel warmer due to the high humidity (nearly 100%). Where dry saunas have humidity between 10-20% and a temperature around 80-100 degrees Celsius at level of the head while sitting up.
The physiologic changes in heated muscle include increase carbohydrate utilization and possible improvement in insulin sensitivity as well. Some other small studies have found that sauna bathing can help decrease total cholesterol and LDL (bad cholesterol) while increasing (HDL) good cholesterol. The positive effects went away 1-2 weeks after the participants stopped using the sauna. The magnitude of these changes were similar to those seen in moderate-intensity exercise.
Many of us have take nitric oxide supplements, or nitric oxide precursors such as citruline and L-arginine to get a better pump or to look more vascular. It was found that hamsters that underwent sauna treatment for 4 weeks had increased expression of nitric oxide synthase (an enzyme that produces NO) compared to those that didn’t undergo sauna therapy. Sauna therapy also decreased “afterload” which is the force that the heart has to overcome to pump blood to the body. Maybe this best can be though of as relaxing the vascular system making it easier for the heart to pump. The blood vessels have smooth muscle in them and they are essentially less ‘clamped down.’ This makes sense in two ways, one because NO relaxes the vessels and two because the vessels especially in the skin dilate in an effort to cool the body down faster. In humans it been observed that sauna use decreases diastolic blood pressure, your blood pressure when your heart is relaxed.
A study published in 2015 in JAMA Internal Medicine found important benefits of sauna use. They found increased use of the sauna was associated with reduced risk of sudden cardiac death, coronary vascular disease, and all cause mortality. The study followed people for around 20 years and found that those who used the sauna more frequently had a lower risk of death. Benefits of sauna use also include increased appetite and decreased reporting of aches and pains in those who are mildly depressed. Researchers have also looked at the incidence of the common cold in those who use sauna baths regularly. They found that there were fewer episodes of the common cold in those that used the sauna. However, the length and severity of the cold if you were to get one was unchanged. When athletes and non-athletes used sauna one time they found that white blood cell count (cells that fight off infection) were increased in the athlete population after a sauna. The researchers thought that this might indicate a faster mobilization of immune cells in athletes. They even suggested that sauna bathing might enhance immunologic defense. Further studies of the benefits of sauna use in competitive male runners found increased endurance and running performance after 3 weeks of post-exercise sauna bathing.
Pseudo-science warning! If you have thought about a sauna you probably couldn’t help but think the thought “sweating out the toxins.” Researchers found there was no difference in “toxin” excretion rates between infrared, exercise, dry or wet saunas.
No doubt the sauna experience is extreme, there are big shifts in fluid, heart rate, and changes in blood pressure. Dry saunas have reporitly greater losses of body water compared to wet saunas about a pound and half of body water per session vs 0.8 lbs in the wet sauna. Wet saunas tend to increase heart rate more than dry sauna. You should always check with your doctor before deciding to use a sauna, especially if you have medical problems. The safety of saunas has been explored in in a few studies one group found that 60 degree C sauna bathing was safe and actually improved symptoms in those with chronic systolic heart failure (heart not pumping strongly.) Other studies have made the claim that sauna use has been well tolerated and posed no health risks to healthy people from childhood to old age. They noted decreased systolic blood pressure, increased ejection fraction (percentage of blood the heart squeezes out with each beat) and improved exercise tolerance. For those who cannot tolerate exercise thermal therapy such as sauna bathing has been mentioned by researchers as a possible alternative to exercise.
Summary of the researched benefits of sauna use
- decreased diastolic blood pressure
- decreased aches and pains and increased appetite in those who are mildly depressed
- decreased muscle fatigue
- decreased bad cholesterol and small but significant increase in good cholesterol
- fewer common colds
- decreased mortality
- improved exercise endurance
- improved immune function
- increased nitric oxide for better pumps and vascularity
- decreased symptoms in those who have systolic heart failure
Sources for benefits of sauna use:
Effect of temperature on muscle metabolism during submaximal exercise in humans.
Beneficial effects of sauna bathing for heart failure patients
Regular Sauna Bathing and the Incidence of Common Colds
Human Excretion of Bisphenol A: Blood, Urine, and Sweat (BUS) Study
The effect of sauna bathing on lipid profile in young, physically active, male subjects.
Changes in the lipid profile of blood serum in women taking sauna baths of various duration.
Effect of post-exercise sauna bathing on the endurance performance of competitive male runners.
Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events
The Medical Risks and Benefits of Sauna, Steam Bath, and Whirlpool Use