Some people believe saunas have general health benefits, and the heat in saunas or hot baths can kill coronavirus.
Hot temperatures may kill viruses on surfaces. The danger with very hot baths is that you could burn or scald your skin. But taking a sauna or hot bath will not affect coronavirus if you are already infected. Your core body temperature does not rise in hot conditions.
There is a theory that saunas protect against infection because they “boost the immune system” or lead to “detoxification” of the body. It is unclear what is meant by either of these things. The liver automatically breaks down toxins in the body, without help from saunas.
Sharing a public sauna could expose you to infection. If you have your own sauna, you can continue to enjoy it, but it is unlikely to protect you from coronavirus.
Where did the story come from?
Some sauna manufacturers have made claims that saunas can protect against COVID-19. Manufacturers are unlikely to be reliable sources of information as they have a vested interest in persuading people of the benefits.
The Sky story reports that saunas are a good way to stay healthy. However, the source adds advice to drink vodka and work hard in the fields, without giving any evidence as to how these measures would help.
What is the basis for the claim?
There have been no clinical studies looking at whether taking saunas or hot baths can protect against the virus that causes COVID-19.
Coronaviruses as a group generally survive for short periods of time in raised temperatures and higher humidity, according to the US Centers for Disease Control and Prevention. However, we do not know what temperature is needed to inactivate the virus responsible for COVID-19. Also, while hot temperatures might affect viruses on the surface of the body (the skin), they are unlikely to affect the virus once it has infected the body’s cells.
We found one small study published in 1990 which seemed to show that people told to take one to two saunas a week were less likely to get a common cold over a 6 month period than those told not to use saunas. However, this study had only 25 volunteers in each arm, so is too small to be conclusive, and participants were not randomly assigned to the groups.
More importantly, we do not know whether measures that affect the common cold virus will also affect the virus that causes COVID-19.
There is little other evidence from reviews of trials that saunas have any effect on people’s chances of catching infectious airways disease, or on their symptoms if they catch an infection.
General claims about saunas “boosting the immune system” or “helping detoxification” do not have a scientific basis. It is unclear what the people making the claims mean by these phrases.
What do trusted sources say?
The World Health Organisation says: “Taking a hot bath will not prevent you from catching COVID-19. Your normal body temperature remains around 36.5°C to 37°C, regardless of the temperature of your bath or shower. Actually, taking a hot bath with extremely hot water can be harmful, as it can burn you.”
Analysis by EIU Healthcare, supported by Reckitt Benckiser