Repeated use of saunas could help people cope better in heatwaves, according to scientists studying heat adaptation. As summer temperatures soar, many are turning to saunas not just for relaxation but as a potential strategy to build resilience against extreme heat. This article explores the growing evidence behind heat training and how passive heat exposure might prepare your body for hotter days.
How Sauna Use Builds Heat Tolerance
Prof Jari Laukkanen, a cardiologist at the University of Eastern Finland, has researched the health benefits of saunas for years. He explains that repeated heat exposure triggers physiological adaptations similar to those seen in athletes who train in hot conditions. These adaptations include earlier and more efficient sweating, improved skin blood flow, and expansion of plasma volume, all of which reduce cardiovascular strain during subsequent heat exposure.
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“Regular heat exposure may help the body regulate temperature more efficiently,” says Laukkanen. This means that by regularly using a sauna, you might train your body to handle heatwaves with less discomfort and lower health risks.
What the Science Says About Passive Heat Exposure
Dr Jessica Mee from the University of Worcester is currently recruiting participants to study whether regular hot water immersion can improve the body’s response to heat. Her research adds to a growing body of evidence that passive heat exposure—such as sauna bathing or hot baths—can mimic some benefits of active heat training. The key is consistency: repeated sessions over weeks or months produce the most significant adaptations.

While saunas are not a replacement for staying hydrated or following official heatwave advice, they may offer an additional tool for those who want to proactively improve their heat tolerance.
Sauna vs. Hot Water Immersion: Which is Better?
Both saunas and hot water immersion can trigger heat adaptation, but they differ in intensity and convenience. Saunas typically expose you to dry heat (70-100°C), while hot baths use wet heat (40-42°C). Here’s a quick comparison:
| Method | Temperature | Duration | Key Benefit |
|---|---|---|---|
| Sauna | 70-100°C dry heat | 10-20 minutes | Rapid sweating, cardiovascular conditioning |
| Hot water immersion | 40-42°C wet heat | 15-30 minutes | Whole-body immersion, easier to tolerate for some |
Both methods have shown promise in studies, but individual preference and access will determine which is more sustainable for you.
Practical Tips for Sauna Heat Training
If you’re considering using saunas to improve heat tolerance, start slowly and listen to your body. Here are key takeaways:
- Begin with shorter sessions (5-10 minutes) and gradually increase to 15-20 minutes.
- Stay hydrated before and after each sauna session.
- Avoid alcohol and heavy meals immediately before use.
- Combine sauna with cold plunges if available, as the contrast can enhance recovery.
- Consult your doctor if you have heart conditions or are pregnant.
Real-World Impact: Community Sauna Baths See Bookings Rise
Nicola Pegues, head of operations at the not-for-profit Community Sauna Baths, observed that bookings initially fell when temperatures rose but have since recovered. “You get real relief out of it actually,” she says, noting that their outdoor sites allow people to cycle between saunas and cold plunges. This suggests that even during heatwaves, people find value in controlled heat exposure.
As the UK experiences its fourth heatwave of the year, with the UK Health Security Agency issuing alerts, understanding how to adapt to heat becomes crucial. While saunas won’t eliminate the risks of extreme heat, they may offer a proactive way to build resilience.
Should You Try Sauna Heat Training?
The evidence is promising, but it’s not a one-size-fits-all solution. If you enjoy saunas and have no medical contraindications, incorporating regular sessions could be a beneficial habit. However, always prioritize official heatwave safety advice, such as staying indoors during peak hours, drinking water, and checking on vulnerable people.