As the UK grapples with its fourth heatwave of the year, recent studies suggest that regular sauna use may enhance our ability to withstand extreme heat. With the UK Health Security Agency issuing alerts across various regions, the conversation around heat training has gained momentum. Experts are exploring whether repeated exposure to heat could serve as a valuable tool in preparing for increasingly scorching summers.
The Rise of Sauna Culture
This summer has seen an uptick in sauna popularity, with a notable shift in public perception. Initially, as temperatures climbed, many sauna venues reported a decline in bookings. However, the trend has reversed, according to Nicola Pegues, head of operations at Community Sauna Baths. “Now we’re witnessing a surge in bookings,” she noted, highlighting the appeal of outdoor facilities that combine saunas with cold plunges. “People experience genuine relief,” Pegues added, underscoring the therapeutic effects of this practice.
Understanding Heat Adaptation
Professor Jari Laukkanen, a cardiologist at the University of Eastern Finland, has researched the health benefits of sauna bathing extensively. He asserts that consistent exposure to heat can condition the body to better manage high temperatures. “This concept is well established in sports physiology, where athletes employ heat exposure to enhance their tolerance before competing in hot conditions,” Laukkanen explained.
He elaborated on the physiological adaptations that occur with repeated heat exposure, including improved sweating efficiency, enhanced blood flow to the skin, increased plasma volume, and reduced cardiovascular stress during subsequent heat exposure. “In essence, regular heat exposure can significantly improve the body’s temperature regulation,” he said.
The Role of Regular Heat Exposure
Dr. Jessica Mee from the University of Worcester is currently recruiting participants for a study focused on how routine hot water immersion might affect the body’s heat response. She emphasised that those accustomed to heat tend to manage it more effectively. “Individuals who regularly experience heat are more likely to pace themselves wisely, maintain hydration, and identify their body’s warning signs more promptly,” Mee noted.
However, it is important to recognise that not everyone will experience the same benefits from heat training. Dr. Heather Massey, an expert in extreme environments at the University of Portsmouth, pointed out that the success of heat acclimation depends largely on the body’s capacity to increase sweating and blood flow to the skin.
Safety precautions are also paramount. Laukkanen cautioned that individuals with certain medical conditions—such as acute illness, unstable angina, a recent heart attack, or uncontrolled low blood pressure—should avoid heat exposure until they receive medical guidance.
The Science of Heat Training
Experts agree that effective heat training typically involves 40 to 60 minutes of heat exposure each day for a minimum of four to six days, with benefits lasting for about a week. While some sauna facilities are marketing their services as a way to combat heatwaves, experts advise that the suitability of sauna use during extreme heat depends on individual health and the level of supervision provided.
Laukkanen emphasised that heat adaptation should not be seen as a substitute for protective measures against heat-related illnesses. “Currently, there is limited evidence to suggest that using a sauna during a heatwave offers protection against heat-related conditions,” he stated. He further explained that the advantages are likely linked to long-term adaptations gained through regular heat exposure, rather than immediate relief during a heatwave.
Dr. Mee reinforced this point, stating, “Heat acclimation is intended as a preparatory strategy for milder months, rather than a coping mechanism for the hottest days of the year.” She cautioned against the risks of layering thermal challenges, particularly during periods of extreme heat, when individuals may already be experiencing sleep deprivation, dehydration, and increased cardiovascular strain. “This combination can create a profile conducive to heat-related illnesses,” she warned.
The Need for Caution
It is critical to acknowledge that many studies on heat acclimation have been conducted in controlled environments, where temperature and exposure times were meticulously monitored, and participants were supervised throughout. Dr. Mee expressed concern about the safety and effectiveness of applying these findings to unsupervised hot baths at home, noting that the immediate risk of fainting is a serious consideration.
In light of these findings, Laukkanen advocates for adherence to public health guidelines during heatwaves. “Regular heat exposure should complement, not replace, fundamental safety measures,” he advised. Staying hydrated, avoiding strenuous activities during peak heat hours, and caring for vulnerable populations remain the most crucial strategies to mitigate heat-related risks.
Why it Matters
As climate change continues to elevate the frequency and intensity of heatwaves, understanding how to prepare for and cope with extreme temperatures is essential for public health. While sauna use may provide some long-term benefits in heat adaptation, it is vital to approach this practice with caution and not rely solely on it during periods of extreme heat. Public health measures and personal safety should always take precedence to protect the health of individuals and communities alike.