The sauna will help you protect yourself from viruses!

An important positive and long-term effect of regular visits to the sauna is the strengthening of the body’s own defense system. Temperature changes during a sauna stay and later cooling the body in cold water make the metabolism and immune system stronger – at the same time the risk of inflammation in the body is reduced. With a good immune system, disease-causing pathogens don’t stand a chance. Regular use of the sauna allows you to prevent colds and other infections, such as the infection caused by the coronavirus, in the long term.

Let’s start with some basic information

The mouth, nose and throat are lined with a special layer of cells, the so-called mucous membrane. Although mucus is mainly made up of water, it has a very important function. It is a protective layer for cells, maintains proper hydration and catches unwanted particles of dust, pollen, mites and the most unwanted – bacteria and viruses – from the inhaled air. The mucus also contains antibacterial substances and protective enzymes. It’s the first line of protection against viruses.

Dry air inhibits the regeneration of the mucous membrane

Most viruses are caught through the mucous layer before they threaten us. Often, the air we breathe dries out our mucous membranes, especially during the heating season, which unfortunately makes it easier for unwanted guests to get there. Dry air is an ideal factor facilitating access to our body for rhinoviruses, which cause upper respiratory tract infections, influenza virus and COVID-19. The optimal humidity for the human body is between 25%-70%. ^[1]If the relative humidity drops below 20%, the mucous layer dries out and our antiviral protection becomes very limited,^[2] which means we are more likely to get sick.

Sauna to the rescue

The humidity in a typical sauna, if the stones are regularly poured with water, can reach up to 80%. This creates ideal conditions for the regeneration of the mucous layer and dried tissue. After rebuilding the lost protective layer through the moist air, we are ready and armed again for battle. Even if some viruses manage to slip through the first line of defense, the hot air in the sauna will quickly kill them. Most viruses cannot tolerate high temperatures. Such a virus is, for example, the rhinovirus that causes colds. According to many studies, the virus multiplies at temperatures lower than 33°C. For this reason, rhinoviruses cause infections in the upper respiratory tract because they cannot survive deeper in the human body, where temperatures are higher. Just 20 minutes spent at 45°C activates our immune system and reduces the possibility of rhinovirus multiplication by up to 90%.^[3]

Sauna and COVID -19

High temperatures are also not the optimal environment for the development of the Covid-19 virus for several important reasons. Coronaviruses are surrounded by a special lipid layer that protects them as they move. Such viruses are relatively resistant to cold and therefore cause many infections during the winter. However, the lipid layer that protects them can be destroyed at high temperatures between 55-65°C, in just 15-30 minutes. ^[4]At 80°C, it only takes 1 minute! The human body is able to withstand such temperature without any problems, Covid-19 is not! Additionally, the coronavirus does not tolerate an alkaline environment. At high temperatures, we breathe more often and deeper, which increases the pH level in our blood. Under such conditions, the virus cannot multiply, becomes inactive or is completely destroyed.^[5]

Is it really that simple?

The conclusion is obvious – regular sauna use will protect us from viruses. However, it’s not that simple. We must bear in mind that even if the thermometer in the sauna shows us a temperature of 120°C, the temperature inside our body will not increase by more than just a few degrees, so the viruses that have already penetrated our body will not be destroyed by the high temperature. It should be noted that sauna baths are not a miraculous remedy to fight viruses that have already entered our body or when we are already sick. Sauna baths can be treated as a very effective preventive measure in the fight for health and our immunity, a way to regenerate the nasal mucous layer that has the first contact with them and a way to get rid of viruses found in the upper part of our respiratory system. A sauna will not heal us when the virus is already in our body or when we are already weakened by it. Then sauna baths have to be postponed. However, instead of fighting diseases and viruses that attack us, it is worth thinking about how to effectively protect ourselves against them. Regular use of the sauna (at least once a week, and preferably 3 times or more) immunizes the body, and thus reduces the possibility of infection also caused by the coronavirus to a minimum.

^[1] Täheväli Stroh, Lea. Maja ja niiskus: Praktilisi nõuandeid niiskuskahjustuste ennetamiseks (Buiding and moisture: Practical guidlines to prevent moisture damage). Tallinn, Ajakirjade Kirjastus, 2005.
^[2] Kudo et al. Low ambient humidity impairs barrier function and innate resistance against influenza infection. Proceedings of the National Academy of Sciences of the United States of America (PNAS), May 28, 2019, 116 (22).
^[3] Conti et al. Antiviral Effect of Hyperthermic Treatment in Rhinovirus Infection. Antimicrobial Agents and Chemotherapy, April 1999.
^[4] Cohen, Mark. Turning up the heat on COVID-19: heat as a therapeutic intervention. F1000Research, 2020, 9:292.
^{[ 5]} Cohen, Mark. 2020, p. 4.