Heat therapy: the benefits of getting sweaty
From the Turkish hammam to the Finnish sauna, humans have been getting sweaty for centuries – we test out the hot sessions meant to increase lifespan and reduce stress
words Lotte Bowser
Earlier this year, I took part in my fourth temazcal ceremony in Lisbon. It’s an ancient South American tradition that harnesses the power of heat to cleanse the mind, body and soul. While the rituals vary from one lineage to the next, the premise of the temazcal is more or less the same every time; the igloo-shaped sweat lodge represents the womb of the Aztec goddess Tonantzin, or ‘Mother Earth’. Participants are invited to undergo a purification process inside the lodge, a ‘rebirth’ of sorts, aided by the heat, darkness and medicinal plants. Here’s how I found it.
After two intense hours of chanting songs in pitch-black while a shaman called Carlos poured water infused with herbs over hot volcanic rocks inside the lodge, I crawled back out into daylight on all fours, gasping for air. I felt reborn alright! But not because I had been sweating enough buckets to rid myself of the debaucherous sins I had committed the weekend before. Really, I left feeling like I had won over the voice inside my head that was screaming to get out, that told me I couldn’t withstand the heat. It was as much of a mental triumph as it was physical – and I felt amazing for it.
Personal experience aside, what are the proven benefits of heat therapy? From the Turkish hammam, the Russian banya, the Japanese onsen, and the Finnish sauna, humans have been getting sweaty for centuries, and for good reason. In recent decades, with Finland at the forefront of the research, heat therapy has been shown to increase our lifespan, improve our physical and mental health, and reduce the risk of certain diseases.
And let’s geek out for a moment by taking a look at the mechanisms behind the heat, and what it actually does to our bodies. According to American biologist and sauna enthusiast Dr. Rhonda Patrick, exposure to extreme heat stresses the body and causes mild hyperthermia – that’s an increase in the body’s core temperature. The amount of work the heart performs to address the body’s need for oxygen increases by 60 to 70%, while the heart rate and amount of blood pumped around the body stays the same. 50 to 70% of blood flow is redirected from the core to the skin to facilitate sweating, cooling the body to regulate our core temperature, as well as improving our heat tolerance.
This acclimatisation to the heat is likely due to a biological process known as hormesis, a compensatory defense response following exposure to a mild stressor. “Hormesis triggers a vast array of protective mechanisms that not only repair cell damage, but also provide protection from subsequent exposures to more serious stressors,” Patrick tells Woo.
Let’s drill down into the data.
Findings from an ongoing study of over 2,000 men in Finland showed that frequent sauna users were 40 percent less likely to die from all causes of premature death, regardless of their age, activity levels, and lifestyle factors. There was also a 27 to 50 percent reduction in cardiovascular-related mortalities, such as heart attacks and strokes, among those who used a sauna 2 to 7 times per week.
After just two 30 minute sauna sessions a week over a period of three weeks, a group of distance runners in New Zealand were reported to have experienced an improvement to their endurance levels. The time it took them to run until exhaustion increased by 32 percent compared to their normal baseline.
Heat exposure can also have a positive impact on our cognitive and mental function. The body’s key players in this are the hormones norepinephrine and prolactin. Norepinephrine enhances our focus and attention, while prolactin promotes myelin growth which makes our brain function faster. Finnish women who took part in two sauna sessions a week experienced a 86 percent increase in the secretion of norepinephrine and a 510 percent increase in prolactin after the first session.
Another long-term study involving nearly 14,000 men and women in Finland showed that during the first 20 years of follow-up, the risk of dementia among those who reported 9 to 12 sauna sessions per month was less than a half of the risk of those who had sauna sessions only 0 to 4 times per month. The decrease of that risk was still evident after nearly 40 years.
Last but by no means least, the heat can play a role in combating mental health issues too. A clinical trial in the US revealed that participants who were diagnosed with depression experienced an acute antidepressant effect after a single session of whole-body hyperthermia, which persisted for six weeks after treatment.
Compelling, huh? Don’t just take our word for it though. Don your togs, get to your local gym and get a sweat on. Your future self will thank you for it.