Sauna sessions boost the immune system A short session in the sauna can improve a person's immune system by temporarily boosting the number of white blood cells circulating the body. 20 April 2026 A quick stint in the sauna could give your immune system a subtle but meaningful lift, according to new research. Using a sauna can boost the immune system Scientists in Finland have found that just one 30-minute sauna session can temporarily boost the number of white blood cells circulating in the body - key players in fighting off infection.