Sweating has long been used as a therapy. The Mayans used sweat houses 3.000 years ago, according to Harvard Health Publications. In Finland, saunas have been used for thousands of years, and 1 in 3 Finns still use them. In the United States (U.S.), there are thought to be over a million saunas.
A sauna is typically a room heated to between 70° to 100° Celsius or 158° to 212° Fahrenheit.
Traditional Finnish saunas usually use dry heat, with a relative humidity that is often between 10 and 20 percent. In other sauna types, the moisture is higher. Turkish-style saunas, for example, involve a greater level of humidity.
A sauna use can raise the skin temperature to roughly 40° Celsius or 104° Fahrenheit.
As the skin temperature rises, heavy sweating also occurs. The heart rate rises as the body attempts to keep cool. It is not uncommon to lose about a pint of sweat while spending a short time in a sauna.
Types of saunas
There are several types of sauna, based on how the room is heated.
Wood burning: Wood is used to heat the sauna room and sauna rocks. Wood-burning saunas are usually low in humidity and high in temperature.
Electrically heated: Similar to wood-burning saunas, electrically-heated saunas have high temperatures and low humidity. An electrical heater, attached to the floor, heats the sauna room.
Infrared room: Far-infrared saunas (FIRS) are different to wood-burning and electrically-heated saunas. Special lamps use light waves to heat a person’s body, not the entire room. Temperatures are typically lower than other saunas, but the person sweats in a similar way. Usually, infrared saunas are about 60° Celsius.
Steam room: These are different from saunas. Instead of dry heat, a steam room involves high humidity and moist heat.
The main benefits proposed for saunas are for relaxation and cardiovascular health. However, a sauna may not be suitable for everyone.
Regardless of how a sauna is heated, or the humidity level, the effects on the body are similar.
When a person sits in a sauna, their heart rate increases and blood vessels widen. This increases circulation, in a similar way to low to moderate exercise depending on the duration of sauna use.
Heart rate may increase to 100-150 beats a minute while using a sauna. This may bring some health benefits.
Health benefits of using sauna:
Increased circulation may help reduce muscle soreness, improve joint movement, and ease arthritis pain.
Reducing stress levels
As the heat in a sauna improves circulation, it may also promote relaxation. This can improve feelings of well-being.Saunas are huge stress fighters. Thanks to sugar, coffee, lack of sleep, stressed adrenals, and toxic chemical exposure, many of us are stuck in the sympathetic or “fight or flight” state. Saunas encourage our bodies to go into the parasympathetic state, which allows us to de-stress, digest, rest, and heal.Stress reduction helps to lower stress hormones (cortisol). When cortisol is kept in balance, thyroid, insulin, DHEA, testosterone, and estrogen are also kept in balance. In fact, progesterone levels can increase if we keep our cortisol in healthy range. Saunas help the adrenals secrete aldosterone, which helps keep electrolytes in balance too.
Improving cardiovascular health
The reduction in stress levels when using a sauna may be linked to a lower risk of cardiovascular events.
One study, conducted in Finland, followed 2,315 men ages 42 to 60 over the course of 20 years. Findings suggested that people who use a sauna may have a lower risk of dying from cardiovascular disease.
Of the participants in the study, a total of 878 died from cardiovascular disease, coronary artery disease, or sudden cardiac death. Participants were categorized by how often they used a sauna, including once a week, two to three times a week, and four to seven times a week.
After adjusting for cardiovascular risk factors, increased sauna use was linked with a reduced risk of fatal cardiovascular-related diseases.
Participants who used the sauna two to three times a week were 22 percent less likely to experience sudden cardiac death than those who only used it once a week. Those who used a sauna four to seven times a week were 63 percent less likely to experience sudden cardiac death and 50 percent less likely to die from cardiovascular disease than those who only used a sauna once a week.
More research is needed to find out if there is a definite link between sauna use and a decrease in deaths from heart disease.
Sauna use may also be associated with lower blood pressure and enhanced heart function.
While studies may be promising, sauna use should not replace an exercise program to keep the heart healthy. There is more evidence to support the benefits of regular exercise.
A dry sauna dries the skin during use. Some people with psoriasis may find that their symptoms reduce while using a sauna, but those with atopic dermatitis may find that it worsens.
People with asthma may find relief from some symptoms as a result of using a sauna. A sauna may help open airways, loosen phlegm, and reduce stress.
Lower risk of Alzheimer’s?
In 2016, researchers from Finland published findings of a 20-year study that linked sauna use with a lower risk of dementia and Alzheimer’s disease. The study involved 2,315 healthy men aged from 42 to 60 years.
Those who used a sauna 2 to 3 times per week were 22 percent less likely to get dementia and 20 percent less likely to get Alzheimer’s than than those who did not use a sauna. Those who used a sauna four to seven times a week were 66 percent less likely to get dementia and 65 percent less likely to get Alzheimer’s than those who used a sauna once a week.
However, the results do not prove that a sauna causes the reduction in risk. It may be that people with dementia do not use a sauna. More research is needed to to confirm these findings.
Health risks and precautions
Moderate use of a sauna appears to be safe for most people. However, a person with cardiovascular disease should speak to a doctor first.
Blood pressure risks
Switching between the heat of a sauna and cold water in a swimming pool is not advisable, as it can raise blood pressure.
A sauna use may also cause blood pressure to fall, so people with low blood pressure should talk to their doctor to make sure sauna use is safe.
People who have recently had a heart attack should also talk to their doctor first.
Dehydration can result from fluid loss while sweating. People with certain conditions, such as kidney disease, may be at a higher risk of dehydration.
The increased temperatures can also lead to dizziness and nausea in some people.
To avoid any negative health effects, the following precautions are also advised:
Avoid alcohol: Alcohol increases the risk of dehydration, hypotension, arrhythmia, and sudden death.
A year-long studies of peopl e in Finland who experienced sudden death showed that in 1.8 percent of cases, the person had had a sauna within the last 3 hours, and in 1.7 percent of cases, they had done so in the last 24 hours. Many of these had consumed alcohol.
Limit time spent in a sauna: Do not spend more than 20 minutes at a time in a sauna. First-time users should spend a maximum of 5 to 10 minutes. As they get used to the heat, they can slowly increase the time to about 20 minutes.
Drink plenty of water: Whatever type of sauna a person uses, it is important to replace the fluids lost from sweating. People should drink about two to four glasses of water after using a sauna.
Avoid sauna use if ill: People who are ill should also wait until they recover before using a sauna. Women who are pregnant or those with certain medical conditions, such as low blood pressure, should ask their doctor before sauna use.