Sauna helps to take the sweat out of exercise
Think sauna and exercise probably isn’t the first image that springs to mind. But a group of University of Eastern Finland researchers, led by cardiology professor Jari Laukkanen, has found a link.
Findings of their study in the Journal of Human Hypertension and the European Journal of Preventive Cardiology show a 30-minute sauna provides the heart-healthy benefits of medium-intensity exercise.
That can seem like a dream to couch potatoes who enjoy “chillaxing” in a sauna.
At heart, stepping into a sauna is about having a good sweat in a controlled heated environment to boost health on a variety of levels.
Sweating is natural and “an impulse”, medical experts say. Some research shows that sweat boxes, baths, lodges or houses date back about 3,000 years to the Mayans of Central America who used sweat houses for religious ceremonies and for the health benefits.
Other research suggests that the Finns were at it even earlier, around 7,000 BC.
So popular are saunas in Finland that it’s common for many homes to have one built in, or at the very least access to one close by.
All cultures have ways of using heat spaces for relaxation, ritual and therapy. These range from open-air ancient Roman baths to modern indoor Turkish steam baths, American hot tubs, down to the drier heat of a “Finnish bath” as a sauna is sometimes called.
A real Finnish sauna is a dimly lit wooden room where the temperature rises upwards of 80°C. Soft woods, such as spruce, aspen and oak, are commonly used for seating, as they don’t absorb heat and remain comfortable to the touch of bare skin.
There is no music in a traditional sauna. The only sounds are the occasional hissing from water thrown on hot stones to give off a vapour. In Finland, there may also be a bit of backslapping with a brush of birch leaves to stimulate circulation further.
Sauna lovers claim a range of benefits from a meditative environment that is conducive to deep relaxation. These include destressing, detoxing, better brain and heart health, pain relief from chronic conditions such as fibromyalgia and arthritis and increased athletic endurance.
Yet popularity is one thing, efficacy and safety another. So just how can sitting still in a birthday suit in a wooden box give the benefits of exercise? Are there other benefits? And what about the risks?
An earlier population study by Laukkanen’s group shows that regular sauna bathing is associated with a reduced risk of coronary diseases and sudden cardiac death as well as hypertension. Their study also suggests that saunas help to reduce the risk of dementia diseases, the most well-known of which is Alzheimer’s.
Scientists have explained the mechanisms of action by which saunas can boost heart health. These include increased skin temperature that rises rapidly to about 40°C and skin blood flow that increases from 5% to 10%, becoming 50% to 70% of the “cardiac output”.
Cardiac output is the medical term for the number of heart beats per minute (heart rate) times the (stroke) volume of blood heart ventricles pump out with each heartbeat.
In their research, the Finnish researchers explain the psychological mechanisms of exercise benefits in a setting of 100 participants. A major factor is the heat that raises the body’s “core” temperature.
There are also myths about sauna benefits. An abiding one is that sauna sessions make great fat burners. Just as exercise is shown to be not a good weight loss tool, the same applies to a sauna session. There is no evidence, or at least, none that I could find, to show that a sauna does burn fat.
Evidence on the risks is clear, though relatively rare. It includes having a heart attack after spending time in a sauna.
A 2007 Israel study in the Experimental and Clinical Cardiology journal, for example, shows that acute myocardial infarction (MI, the medical profession’s term for heart attack) and sudden deaths do occur in saunas. However, researchers at Haifa University school of public health say that’s mostly related to alcohol consumption during sauna bathing. They note that alcohol raises the risk of hypotension, arrhythmia and sudden death.
The same study reassuringly says that sauna bathing is “safe for most people with coronary artery disease, stable angina pectoris or old MI”.
But all sauna use comes packaged with caveats. Among these are that anyone with cardiovascular disease should seek a medical doctor’s advice before dipping into that hot air. Ditto for pregnant women.
Research shows that Finnish children have regular access to sauna facilities at local sporting, recreation and swimming centres. Sauna bathing also often takes place as part of physical education lessons or sporting club activities for those over the age of seven.
A 1988 study by researchers at Turku University in Finland noted that Finnish parents have “an empirically acquired understanding of the limits of safe heat exposure” that guides sauna bathing by children.
For the rest, people are likely to boost their fitness in body and mind if they regularly indulge in a sweating session.