Most people don’t like to get hot, apart from when on a sunny vacation. We work hard to keep our environment pretty well controlled. But periodically increasing our core temperature is actually healthful. Saunas are a great way to do this. Let’s find out more.
Saunas have been around for hundreds of year. With the introduction of small infrared saunas suitable for home use, their popularity is slowly increasing in the US. But in Finland, they are a key part of the culture and have been for years.
Finnish Sauna culture
There are over 3 million saunas in Finland – with 5 million inhabitants! That gives an average on one per household! For them, it is a place to relax with friends and family. It is viewed as a necessity, not a luxury.
Saunas are an integral part of the way of life in Finland. Their approach on how to sauna is as follows:
- remove all clothes – considered mandatory
- sit in the sauna (80-100C) for 20-30 minutes, on a small towel
- throw water on the hot stones to warm things up a bit
- on some occasions, gently beat yourself with a bunch of fragrant silver birch “Vihta” to improve circulation further and relax the muscles!
- get ready for the washing lady! In some hotels, a washing lady will enter the sauna and wash every one! Don’t be shy!
- leave the sauna and jump into a cold lake, ocean, or roll in the snow
- repeat the above as many times as you wish! Most Fins repeat at least twice.
Hmmm that roll in the snow part seems the trickiest bit. I remember when we lived in NH, we tried it after being in a hot tub….Envigorating? Couldn’t tell above the screams!
Research on saunas
There is a good amount of scientific research on the use of saunas. Bear in mind, however, that much of it is done in Finland. Obviously, this is because most people sauna frequently there so it is an easy population to follow. However, it also means that the results tend to be expressed in terms of an outcome after a certain number of saunas a week compared to the outcome after only one sauna a week. The comparisons often aren’t to someone having no saunas – as there are so few people in Finland who never or infrequently sauna! Also, it’s good to read the research carefully and see if the sauna research includes that burst of cold afterwards, like the plunge in cold water. Is that part of the reason for the benefit or is it purely the heating aspect?
The Finnish research most commonly uses the Finnish style Dry Sauna (- see below for different types) while nowadays, the infrared sauna is increasingly popular in the US. Does the type of sauna affect the outcome? Side by side comparisons aren’t being studied. However, as the physiological mechanisms of how the heat affects the body seem to be the same, it seems reasonable to presume that a method that increases the core body temperature is what is most important.
The good news is that with all this Finnish research showing such positive results, more research is being done elsewhere, including the US.
Different types of saunas
There are three type of saunas: dry, steam, and infrared.
- Dry sauna – based on the traditional Finnish sauna with low humidity and temps 80-100C
- Steam sauna – higher humidity and lower temperature sauna. Often more uncomfortable than a dry sauna
- Infrared saunas – these use infrared radiation lamps. Can be far-infrared and near-infrared. Far-infrared saunas emit longer wavelengths of infrared light that penetrate the skin to ~0.1mm deep. Near-infrared saunas emit shorter wavelengths that can penetrate the body up to ~5mm.
The dry and steam saunas heat the air in the sauna and thus warm you up from the outside. Infrared doesn’t heat the air, rather it heats the first surface that it meets ie your body – and it penetrates the skin. So the room doesn’t feel hot with infrared, but your body does. This promotes sweating at a lower temperature as it is body itself being heated, not the room.
What happens in a sauna?
When we are in a hot environment, the body tries to cool us down by sweating. However, in a sauna, we will indeed sweat, but that isn’t enough to compensate for the extreme heat. This means that our core body temperature will increase (about 1-3C).
This leads to the following changes in the body:
- norepinephrine increases, resulting in increased heart rate
- increased cardiac output
- the immune system is stimulated
- there is an increase in growth hormone, which promotes muscle repair and prevents atrophy
- increase in levels of Heat Shock Proteins
Health benefits of sauna use
Because of these physiological changes, research has shown the following potential health benefits associated with sauna use:
- relaxation – most people find saunas relaxing
- improved detoxification – sauna use may help flush out toxins from the body, due to the increased sweating. This may help detoxify heavy metals and other toxins such as BPA, phthalates.
- cardiovascular disease – Study: a long-term study showed that those who had frequent saunas several times a week had lower risk of sudden cardiac death and lower all-cause mortality. Many other studies show increased exercise tolerance, increased cardiac output, better prognosis for those with chronic heart failure, and lower oxidative stress.
- depression – whole body hyperthermia and saunas may have anti-depressant effects
- blood pressure – nitric oxide – a vasodilator, is increased during sauna use and may lead to lowered blood pressure. Study: A Finnish study showed that twice-weekly sauna for 3 months resulted in a reduction in blood pressure in hypertensive men from 166/100mmHg to 143/92mmHg. This reduction is equivalent to that seen with blood pressure lowering medication. Another study showed that combining exercise with sauna use showed greater blood pressure reductions than exercise alone, and also resulted in a greater loss of body weight and body fat.
- lipid profiles – regular sauna use may improve lipid profiles with lowering of cholesterol and LDL and increasing HDL levels after 2-3 weeks.
- weight loss – sauna use burns calories which may lead to improved weight loss
- recovery – may speed up recovery from muscular injury caused by exercise and surgery
- performance – may improve athletic performance and endurance
- reduced risk of dementia and Alzheimer’s disease – studies on sauna use show potential to improve vascular function, blood pressure, inflammation and cognition leading to reduced risk of disease
- pain reduction – seen in fibromyalgia and rheumatoid arthritis and other chronic pain conditions.
Guidelines for using saunas
- If you have a health condition, consult with your doctor before you start using saunas
- Avoid saunas if you are pregnant
- Start slowly – just a few minutes to begin with, then gradually work up how long you stay in the sauna. Typically, this is 20-30 minutes.
- Heat responsibly and with someone else. Never alone.
- Don’t use a sauna if you have been drinking alcohol. Never consume alcohol while you are in a sauna
- Stay hydrated – before, during and after.
- Listen to your body. Feeling warm and sweaty is OK. Feeling dizzy and nauseous isn’t OK and means you should leave. If you feel uncomfortable, leave.
- Don’t eat a huge meal beforehand.
- It’s great to do dry brushing beforehand, as this helps with detoxification.
- Shower before and after.
Many athletic clubs, fitness centers, and spas have saunas. If you are a member of one, give it a try after your next work out or just go for the sauna. Get sweatin’!
In the next few blog posts, we’ll dive deeper into the research associated with sauna use and specific health conditions.