A single sauna session sends immune cells surging - ScienceDaily

What the report says

ScienceDaily reported on July 27, 2026, that a Finnish study found a single sauna session may cause a short-lived rise in immune cells circulating in the blood. The report, based on materials from the University of Eastern Finland, said researchers observed the effect after a 30-minute sauna exposure that included a brief cold shower midway through the session.

According to the reported findings, all measured categories of white blood cells increased in participants’ bloodstream after the sauna exposure. The changes included higher levels of neutrophils and lymphocytes, immune cells involved in recognizing and fighting infection. Those two cell types reportedly returned to typical levels within roughly 30 minutes after the session ended, suggesting the response was temporary.

The study also examined cytokines, which are signaling molecules involved in immune regulation. ScienceDaily said average cytokine changes were modest, but some individual responses appeared to vary with how much a participant’s body temperature rose during the sauna session. The same temperature-related pattern was not reported for the white blood cell changes.

The study included 51 adults with an average age of 50 and was published in the journal Temperature. Researchers said the findings may help explain biological mechanisms behind previously reported associations between regular sauna use and health benefits. However, the experiment measured only immediate effects from one sauna session, so it does not show whether repeated sauna bathing produces durable immune changes or long-term health outcomes.