The power of heat and steam: health benefits of saunas

Sauna baths and other similar heat therapies have a long history, with roots dating back to prehistoric times. In fact, it 's a deeply rooted practice in several cultures, including the traditions of ancient Rome, Japan, Turkey, and Finland.

The ancient Romans are famous for their sophisticated bathhouses: the thermae. They featured complex underfloor heating systems (hypocausts), demonstrating an advanced understanding of the therapeutic benefits of heat.

In Japan, onsen (natural hot springs) and sento (public baths) have been used for centuries as communal bathing areas. They are considered important for hygiene, relaxation, and health.

The Turkish bath, or hammam, is also deeply rooted in Turkish culture. Evolving from the traditions of Roman baths, it provides a warm, humid environment believed to purify the body and soul.

Although the Finnish sauna is perhaps the longest-standing tradition of all: evidence suggests it has been used in the Scandinavian country for over 2,000 years, its health benefits are widely recognized.

Sauna bathing, especially traditional ones, is an activity characterized by exposure to high temperatures , often followed by a rapid cool-down. This practice has gained attention for its potential health benefits, backed by numerous scientific studies, as discussed in this article.

But first, let's clarify the differences between dry saunas and steam (wet) saunas. Dry saunas typically operate at high temperatures (around 70-100°C) with very low humidity (10-20%). This type of dry heat can promote profuse sweating and is only tolerable for short periods of time.

Steam or wet saunas, on the other hand, operate at lower temperatures (40-50°C) and humidity levels as high as 100%. This environment can be more intense for the respiratory system and skin due to the dense, warm air, so users with sensitivity to humid heat or chronic respiratory problems should be cautious.

Regarding the proven benefits of saunas, first and foremost, frequent sauna use can reduce the likelihood of sudden cardiac death, coronary heart disease, and cardiovascular mortality . One study found that men who used saunas four to seven times per week had a significantly lower risk of fatal cardiovascular events compared to those who used them only once every seven days.

Furthermore, heat induces vasodilation, improving blood flow and reducing vascular resistance. A study published in the American Journal of Hypertension linked sauna use with a lower risk of developing hypertension.

On a respiratory level, saunas have been shown to improve lung function and reduce symptoms of conditions such as asthma and chronic bronchitis . The heat and steam can help clear mucus from the airways and improve breathing.

For example, according to research published in Respiratory Medicine, sauna bathing improves forced vital capacity (total amount of air exhaled forcefully after a deep inspiration) and forced expiratory volume in 1 second (air exhaled forcefully during the first second of a forced expiration) in people with obstructive lung disease.

And finally, we also see benefits in mental health and stress reduction. The increase in endorphins and other hormones during a session contributes to a feeling of well-being.

By now, many readers may be wondering what happens to the skin, the organ most directly exposed to heat and humidity, but in this chapter we need to discuss both the benefits and potential harms.

On the positive side, sauna baths increase blood circulation and promote sweating, helping to eliminate toxins and impurities. This process can help improve skin clarity and elasticity, which would be beneficial for conditions like acne and for maintaining overall skin health. Additionally, the heat can relax pores, allowing for a deeper cleansing when combined with proper skincare routines.

For people with skin conditions such as eczema or psoriasis, sauna use can both relieve and exacerbate symptoms. Consulting a doctor is recommended to determine suitability.

On the downside, prolonged exposure to heat and humidity can lead to dehydration and aggravate conditions like eczema or psoriasis , as previously mentioned. In general, spending too much time in a sauna can impair the skin's barrier function, leading to dryness and irritation.

And who are saunas recommended for? Most healthy adults can enjoy them. They are also generally considered safe for people with stable cardiovascular conditions, as long as they are used under proper guidance and do not exceed the recommended time limits.

There are exceptions: they are not recommended for people with unstable angina, recent myocardial infarction, or severe heart valve disease. Intense heat can aggravate these conditions and pose risks.

Similarly, although there is some debate, it is generally recommended that pregnant women avoid sauna use, especially during the first trimester , due to the risk of hyperthermia (excessively high body temperature) for the fetus.

Furthermore, in cases of dehydration and heat intolerance, saunas can cause dangerous fluid loss through sweating. It's essential to stay hydrated and limit sessions to the recommended duration (usually 10 to 20 minutes).

In conclusion, sauna bathing offers numerous benefits, particularly for cardiovascular and respiratory health, and can be a valuable practice for maintaining a healthy lifestyle. However, it is essential to consider individual health conditions and consult a specialist if you have any concerns or contraindications.

(*) Professor of Medical-Surgical Nursing, University of Castilla-La Mancha. (**) This is a non-profit organization that seeks to share academic ideas and knowledge with the public. This article is reproduced here under a Creative Commons license.