'The heat helps your body fight infections': why ONE 30-minute sauna session will boost your immunity this autumn

It’s always lovely to escape from the autumn drizzle into a hot and relaxing sauna. But according to a new study from Finland – and, boy, do they know their saunas in Finland – steaming yourself for a short while can also be good for your health.

And in even better news, you don’t need an expensive spa membership – just the occasional session will add some benefit. Researchers at the University of Turku in Finland found that just 30 minutes in a sauna – with a break for a quick cold shower halfway through – causes white blood cells to surge into the bloodstream.

White blood cells are essential to the body's defenses, helping identify and fight infections and other potential threats. The research suggests that sauna bathing may temporarily mobilise immune cells that normally remain in your tissues, allowing them to circulate more widely throughout the body and battling pathogens such as viruses and bacteria. This process is known as immune surveillance.

‘The 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,’ says Ilkka Heinonen, an Academy Research Fellow at the University of Turku.

According to the researchers, the ‘heating and cooling’ effect of adding a brief cold shower to the session increases the effectiveness of the treatment.

Previous research has already linked regular sauna bathing with several potential health benefits, and this latest theory may hold the key to the reasons why.

Although more research is needed to understand the long-term implications, the study reveals that even a single sauna session can rapidly change how immune cells circulate through the body, potentially offering new insight into the biological effects of this popular relaxation practice.

Leicestershire GP Dr Sarah Levy, feels the study makes a lot of sense. ‘There is actually some truth in the old wives’ tale that “You get a cold if you get wet and cold”,’ she says. ‘Getting cold can temporarily reduce the effectiveness of the immune system.

‘It’s therefore not a surprise to hear that a short sauna burst can cause in increase in infection-fighting white blood cells circulating in the blood.’