This hobby is white-hot.
Turns out a well-loved relaxation practice isn’t just good for heart health — it may also help the human body defend against nasty pathogens and diseases.
This week, a team of Finnish scientists released findings showing that just 30 minutes in a sauna — paired with a quick, cooling shower halfway through — resulted in improved circulation of white blood cells. Their presence in the bloodstream is a key part of the body’s immune defense.
After half an hour, the number of neutrophils and lymphocytes, two types of white blood cells that had spiked in the blood of study participants, returned to normal.
Ilkka Heinonen, one of the study’s lead authors, said this pattern could mean the ancient sweating custom — believed to date back at least 10,000 years — helps those immune responders work more efficiently over time.
“This may indicate that sauna bathing mobilizes additional white blood cells into the bloodstream from tissues, where they are then redeposited after the session,” he said.
“This kind of periodic release of white blood cells into the bloodstream is beneficial, as once they leave their storage sites, they are better able to patrol the body and respond to pathogens.”
Other healthy activities release white blood cells into the bloodstream, too, like exercise. This allows the cells to conduct “surveillance” within the body, pinpointing spots that may need some extra backup.
It’s no great shock that this research comes from Finland, a country that’s home to 5.5 million people and 3.3 million saunas.
Across northern Europe, contrast therapy, or extreme cold paired with extreme heat, is more than a cultural pastime — for many, it’s an essential part of daily life and considered the secret to sustained mental, physical and emotional wellbeing.
As of 2020, Finnish sauna culture was even added to the UNESCO Representative List of the Intangible Cultural Heritage of Humanity.
There are several different types of saunas, including dry and wet, and the temperature can reach anywhere between 110 degrees Fahrenheit and well over 200 degrees Fahrenheit in a traditional Finnish setting.
While the general benefits and risks of a spa remain hotly contested among researchers, a recent observational Canadian-Finnish study showed a promising connection between regular sauna use and improved respiratory, cognitive and cardiovascular health.
Quadruple board-certified cardiologist and Qunol partner Dr. Tiffany Di Pietro recently told The Post that sauna-based heat exposure was one of the best things you can do to improve heart health.
“Regular sauna bathing is associated with lower rates of fatal cardiovascular events in observational data,” she said, though she noted that there’s no proof of direct causation.
Still, she added, “it’s compelling and fits with physiologic effects” that come with the territory of greater relaxation, including lowered blood pressure and better vasodilation, or the widening of blood vessels.
Saunas aren’t suitable for everyone, however. Unstable angina, valvular heart disease, a recent heart attack or certain blood pressure issues could be disqualifying conditions for sauna use, and patients should speak with their doctor before settling into a spa.
That said, Nordic folks have raved about their daily sweats and the purported benefits for centuries. And other parts of the world have warmed to the concept, too.
In recent years, saunas have become something of a hot commodity in the US. The wellness-obsessed have lit a fire under the sauna market, which is expected to grow by over $150 million before 2029, with industry players sweating to get in on the action.
