Sauna Bathing and the Immune System
Saunas have been part of Finnish life for centuries, and researchers in Finland are still finding out why they make us feel so good. A new study from the University of Eastern Finland and the University of Turku looked at what a single sauna session does to the immune system.
What the researchers did
The study followed 51 adults with an average age of 50. Each took a 30-minute sauna session with a short cold shower halfway through. The researchers measured their blood to see how different immune cells responded.
What they found
Every type of white blood cell the researchers measured increased in the bloodstream during the session. That included neutrophils, which are often first on the scene when the body fights an infection, and lymphocytes, which recognize specific threats and coordinate the body’s response.
The increase was temporary. Within 30 minutes of finishing, neutrophil and lymphocyte counts were back to their starting levels.
The researchers suggest the heat may release white blood cells from tissue where they’re normally stored, sending them out to circulate. Once in the bloodstream, these cells are better able to patrol the body and respond to threats. This is called immune surveillance, and exercise triggers a similar short-term response.
A few things to keep in mind
Good research comes with limits, and the authors are clear about theirs:
- The study looked only at the immediate effects of one session. It doesn’t show that sauna bathing makes your immune system stronger over time or reduces your chance of getting sick.
- The session included a cold shower, so the results reflect the full sauna-and-cool-down routine, not heat alone.
- Sauna and exercise produce a similar kind of response, but that doesn’t make them equivalent.
What it means for you
This research adds to a growing body of work on why regular sauna bathing is linked to health benefits. It’s one more reason to see your sauna as more than a luxury. It’s a routine that gives your body a real physiological workout, and one you can enjoy at home.
If you’re curious about adding a sauna to your backyard or home, our team at Backyard Living Center would love to help. Stop by our Saskatoon showroom to see our Finnleo saunas in person and talk through what would fit your space.
As always, if you have a heart condition, are pregnant, or have other health concerns, check with your doctor before starting a sauna routine.
Source: Heinonen et al., “Acute Finnish sauna heat exposure induces stronger immune cell than cytokine responses,” Temperature, 2026. Summary via ScienceDaily.