Next time you work out, maybe take a 15-minute sauna when you're done for extra heart health benefits.
That's the main finding of research out of Finland. It found taking a sauna confers additional cardiovascular benefits over exercise alone.
The new study didn't look at how saunas can boost heart health, but other studies have elucidated these benefits. It has been shown "that some of the cardiovascular responses from sauna bathing are comparable to moderate intensity exercise, at least acutely," said study author Earric Lee, a researcher in the faculty of sport and health sciences at the University of Jyväskylä in Finland. The sauna is an integral part of Finnish culture, and there are more saunas than cars in Finland, he said.
People who took a sauna after exercising had lower blood pressure and total cholesterol levels than those who didn't, the study found. Specifically, systolic blood pressure - the upper number in a blood pressure reading - fell by almost 9 mm Hg, and total cholesterol levels went from high to the acceptable range among folks who took a sauna after exercise.
For the eight-week study, 47 fairly sedentary adults, aged 30 to 64, were divided into three groups: resistance and aerobic exercise three times a week for 50 minutes per session; resistance and aerobic exercise three times a week for 50 minutes per session followed by a 15-minute sauna; or no exercise or sauna. Aerobic activity like running or brisk walking gets your heart pumping while resistance exercise builds muscles.
Everyone in the study had at least one risk factor for heart disease, such as high cholesterol, high blood pressure, obesity, smoking, or a family history of heart disease. Participants could leave the sauna before 15 minutes if they were uncomfortable in the heat, but no one did.
People in the exercise-sauna and exercise-only groups showed an increase in their maximum rate of oxygen consumption or VO₂ max compared with people in the control group. VO₂ max refers to how much oxygen your body can use during exercise, and the higher it is, the better your physical fitness.
In addition to the reductions in blood pressure and cholesterol, folks who took a sauna after exercising showed even greater increases in VO₂ max than their counterparts in the exercise-only group, the study showed.
The study was published online July 4 in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.
The new findings add to a growing body of research on the health benefits of saunas, said S. Tony Wolf. He is a postdoctoral scholar in kinesiology at Pennsylvania State University. "The topic of sauna bathing or heat therapy to improve cardiovascular health has been taking off for several years," said Wolf, who has no ties to the new research.
It makes sense that saunas would confer some heart health benefits, he noted. "The heat causes our blood vessels to widen so the body can maintain its temperature, and this increases blood flow and heart rate," Wolf said. "Heat therapy also improves nitric oxide (NO) availability, and NO-mediated blood vessel function is a really important component of cardiovascular health."
Exercise produces similar benefits, he said. "If you superimpose heat with exercise training, you get a synergistic effect," Wolf explained.
It's likely better to take a sauna right after exercise when your body temperature is already high. "You may get to a higher body temperature with exercise followed by sauna bathing than sauna use alone, and the higher body temperature may further stimulate these positive changes," Wolf said.
Dr. Deepak Bhatt is executive director of interventional cardiovascular programs at Brigham and Women's Hospital Heart and Vascular Center in Boston.
"This is a small, but interesting study that supports the incremental value of improving cardiovascular risk factors by using a sauna, above and beyond the benefits of exercise," said Bhatt.
"Further larger studies are needed, though sauna use seems like a potentially promising approach, especially for people who enjoy saunas," added Bhatt, who also has no ties to the research.
Saunas aren't for everyone. "People with severe, unstable cardiovascular disease for whom a low blood pressure might be dangerous should likely avoid saunas, but for people with stable cardiovascular disease, the risks are minimal," he said. "You do have to be careful to not get dehydrated."
The American Heart Association offers tips on controlling blood pressure, including a caution on saunas and blood pressure.
SOURCES: Earric Lee, researcher, faculty, Sport and Health Sciences, University of Jyväskylä, Finland; S. Tony Wolf, PhD, postdoctoral scholar, Pennsylvania State University, University Park, Penn.; Deepak Bhatt, MD, MPH, executive director, interventional cardiovascular programs, Brigham and Women's Hospital Heart and Vascular Center, and professor, Harvard Medical School, Boston; American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, July 4, 2022