Can Sauna Sessions Help the Body Adapt to Heatwaves? What Science Says About Heat Acclimatisation

Introduction: Could Saunas Help Us Handle Hotter Summers?

As heatwaves become more frequent across the UK and many parts of the world, scientists are exploring ways the human body can better cope with extreme temperatures. One surprising area of interest is the traditional Finnish practice of sauna bathing.

Recent research suggests that repeated exposure to heat, including through sauna use, may help the body develop adaptations that improve its ability to manage high temperatures. However, experts warn that sitting in a sauna during a heatwave is not a replacement for staying hydrated, avoiding excessive heat exposure, or following official health advice.

The potential benefits appear to come from long-term heat adaptation rather than using a sauna as an immediate solution when temperatures rise.

How Heat Exposure May Train the Body

The human body has natural systems designed to control temperature. When exposed to heat, the body activates several responses, including sweating and increasing blood flow near the skin. These processes help release excess heat and maintain a stable internal temperature.

Scientists studying heat adaptation have found that repeated exposure to hot environments can strengthen these natural responses. This process is known as heat acclimatisation.

According to research in sports physiology, athletes often use controlled heat exposure before competing in hot climates. The goal is to help their bodies adjust before facing demanding conditions.

Professor Jari Laukkanen from the University of Eastern Finland has studied the effects of sauna bathing and its relationship with cardiovascular health. Research linked to his work suggests that regular heat exposure may lead to changes such as:

• Earlier and more efficient sweating
• Improved blood flow to the skin
• Increased plasma volume, which supports circulation
• Reduced stress on the heart during heat exposure

These changes may allow the body to regulate temperature more effectively.

Why Sauna Use Is Gaining Popularity in the UK

Sauna culture has traditionally been associated with Finland, where regular sauna bathing is a common part of everyday life. In recent years, however, interest in saunas has increased across the UK.

The growth of wellness trends, interest in recovery treatments, and increased awareness of heat therapy have contributed to the rise of new sauna facilities. Industry figures suggest that the UK sauna market has expanded significantly, with more locations becoming available compared with previous years.

This growing popularity has also encouraged researchers to examine whether sauna bathing offers benefits beyond relaxation.

While many people use saunas for stress relief and wellbeing, scientists are increasingly investigating their possible effects on cardiovascular health, immune function, and the body's ability to tolerate heat.

Sauna Research and Health Benefits

Studies have explored how passive heat exposure, such as sauna bathing or hot water immersion, may influence the body.

Research published in scientific journals has suggested that passive heat therapy may improve cardiovascular function, particularly among middle-aged and older adults. Better cardiovascular performance may help reduce strain on the body during periods of high temperature.

Another study involving sauna sessions found changes in circulating white blood cells after a 30-minute sauna session followed by a brief cold shower. White blood cells play an important role in immune system activity, although researchers continue to investigate what these changes mean for overall health.

It is important to remember that individual studies do not prove that sauna use prevents illness. Scientific research often develops gradually, with multiple studies needed before firm conclusions can be made.

Can a Sauna Protect You During a Heatwave?

Although sauna use may help the body adapt to heat over time, experts say it should not be considered a treatment for extreme weather.

Heatwaves can create serious health risks, particularly for older adults, young children, and people with certain medical conditions. High temperatures can contribute to dehydration, heat exhaustion, heatstroke, and increased pressure on the cardiovascular system.

Professor Laukkanen has highlighted that evidence is limited regarding whether using a sauna during an active heatwave directly protects people from heat-related illness.

The possible advantage comes from regular, controlled heat exposure over time. A sauna session before or during a heatwave will not instantly prepare the body for dangerous temperatures.

During extreme heat, public health advice remains essential. People should drink enough fluids, keep homes cool where possible, avoid unnecessary strenuous activity during the hottest parts of the day, and check on vulnerable individuals.

The Difference Between Heat Training and Heat Stress

One important distinction is the difference between controlled heat exposure and uncontrolled heat stress.

A sauna provides a controlled environment where temperature and exposure time can be managed. A heatwave, on the other hand, can expose people to prolonged high temperatures without the same level of control.

Heat adaptation programmes used by athletes are carefully planned. They usually involve gradually increasing exposure while monitoring the body's response.

For everyday sauna users, moderation is important. People should listen to their bodies and avoid excessive heat exposure, especially if they have existing health concerns.

Anyone with heart conditions, blood pressure problems, or other medical issues should seek professional medical advice before beginning regular sauna sessions.

What This Means as Climate Change Increases Heatwaves

Rising global temperatures mean that heat management is becoming an increasingly important health issue. Scientists are exploring various ways to improve resilience, from better urban planning to changes in personal health habits.

Sauna use represents one possible area of research into how the body responds to repeated heat exposure. While it should not be viewed as a solution to climate-related heat risks, it may provide insight into how humans can adapt physiologically.

The idea that controlled heat exposure can strengthen the body's response to hot conditions is not new. It has been studied extensively in sports science and is now attracting wider attention among health researchers.

Conclusion: Saunas May Support Heat Adaptation, But They Are Not a Heatwave Cure

Sauna bathing may offer some benefits by encouraging the body to adapt to heat through repeated exposure. Research suggests that regular sauna use could improve certain temperature regulation responses and support cardiovascular health.

However, a sauna session cannot prevent heat-related illness during a severe heatwave. Staying safe in extreme temperatures still depends on practical measures such as hydration, cooling strategies, and following official health guidance.

As summers become hotter, understanding how the human body responds to heat will become increasingly important. Sauna research provides an interesting example of how traditional practices and modern science can combine to explore new approaches to health and resilience.

Sources

• The Independent, article discussing sauna use and heat adaptation during UK heatwaves, published 30 July 2026.
• Research by Professor Jari Laukkanen, University of Eastern Finland, on sauna bathing and cardiovascular health.
• Studies published in the Journal of Applied Physiology examining passive heat therapy and cardiovascular function.
• Research literature on heat acclimatisation in sports physiology.

Disclaimer

This article is for informational and educational purposes only and does not provide medical advice. Sauna use is not a replacement for official heatwave guidance, medical treatment, hydration, or appropriate precautions during extreme weather. People with existing health conditions should consult a qualified healthcare professional before starting regular sauna sessions or heat exposure practices.