How Saunas Fight Infections
The human body’s primary defense mechanism against illness is fever. In raising our body temperature, saunas may trigger the body into going into “fight mode” before we become infected or symptomatic.
What you should know about saunas and COVID-19
You’ve seen articles talking about how saunas may help fight COVID-19. Are they true? To be honest, we don’t know.
- There’s a lot about COVID-19 that we don’t know. It’s a “novel” coronavirus - meaning new. Scientists are making presumptions based on what they know about other coronaviruses, so there are nuances that may not apply to the virus that causes COVID-19.
- Science takes time. Reliable scientific studies must be:
- Done very methodically with control groups
- Peer reviewed
So what do we know? We know that sauna therapy has been used for wellness for millenia. It’s been used to fight infections for decades and there are modern scientific studies proving that sauna therapy works.
How have saunas been used to fight infection?
The Finns used sauna therapy to prevent typhoid fever in WWII.
Since the late 1950s, sauna therapy has been used to prevent influenza.
A 1990 study showed that sauna therapy may cut the incidence of the common cold in half. We’ve heard the same thing from several Salus customers.
Other studies have been published, some recently, that suggest saunas may be able to help the body shed viral infections and protect against other diseases such as dementia.
How do I use my sauna to fight infection?
One scientific study showed that those who use saunas a minimum 4 times per week, cut their risk of developing pneumonia and other respiratory diseases by half.
Another study shows that saunas trigger the immune system in as little as 15 minutes.
Some articles we’ve seen suggest 30 minutes, five times a week (just like exercise). Don’t worry if you can’t last 30 minutes - just add minutes and degrees over time.
How do saunas increase our immunity?
Saunas are thought to increase immunity in four different ways.
- The human body’s primary defense mechanism against illness is fever. In raising our body temperature, saunas may trigger the body into going into “fight mode” before we become infected or symptomatic.
- Consistent sauna use may slow or even stop viruses from spreading throughout the body.
- Saunas cause short-term stress on the body. That’s why you may be a bit tired when finishing a sauna session if you’re new to saunas. Rather than wearing the body down and making us more susceptible to getting sick, our body learns to adapt and gets stronger against fighting more stressors - like illness.
- Scientists recently made a breakthrough in showing how saunas work specifically against viruses. They found that sauna use increases the amount of “Heat Shock Proteins,” a.k.a. “HSPs,” produced by our bodies. HSPs stop proteins from breaking down and jumpstart our immune systems. In other studies, HSPs were shown to stop the influenza virus from spreading in our bodies.
Many public libraries have databases of scientific studies and you can read the abstracts or even the full articles. Here are English-language articles used to develop this blog entry.
Akasaki Y, Miyata M, Eto H, et al. Repeated thermal therapy up-regulates endothelial nitric oxide synthase and augments angiogenesis in a mouse model of hindlimb ischemia. Circ J 2006;70:463-70.
Akerstrom S, Gunalan V, Keng CT, et al. Dual effect of nitric oxide on SARS-CoV replication: viral RNA production and palmitoylation of the S protein are affected. Virology 2009;395:1-9.
Akerstrom S, Mousavi-Jazi M, Klingstrom J, et al. Nitric oxide inhibits the replication cycle of severe acute respiratory syndrome coronavirus. J Virol 2005;79:1966-9.
Chang CC, Wu JM. Modulation of antiviral activity of interferon and 2',5'-oligoadenylate synthetase gene expression by mild hyperthermia (39.5 degrees C) in cultured human cells. J Biol Chem 1991;266:4605-12.
Chen L, Liu P, Gao H, et al. Inhalation of nitric oxide in the treatment of severe acute respiratory syndrome: a rescue trial in Beijing. Clin Infect Dis 2004;39:1531-5.
Conti C, De Marco A, Mastromarino P, et al. Antiviral effect of hyperthermic treatment in rhinovirus infection. Antimicrob Agents Chemother 1999;43:822-9.
Ernst E, Pecho E, Wirz P, et al. Regular sauna bathing and the incidence of common colds. Ann Med 1990;22:225-7.
Gryka D, Pilch WB, Czerwinska-Ledwig OM, et al. The influence of Finnish sauna treatments on the concentrations of nitric oxide, 3-nitrotyrosine and selected markers of oxidative status in training and non-training men. Int J Occup Med Environ Health 2020;33:173- 85.
Guzhova IV, Arnholdt AC, Darieva ZA, et al. Effects of exogenous stress protein 70 on the functional properties of human promonocytes through binding to cell surface and internalization. Cell Stress Chaperones 1998;3:67-77.
Hartmann A. [Asiatic flu in 1957; sauna baths as prophylactic measure]. Hippokrates 1958;29:153-4.
Hirayama E, Atagi H, Hiraki A, et al. Heat shock protein 70 is related to thermal inhibition of nuclear export of the influenza virus ribonucleoprotein complex. J Virol 2004;78:1263-70.
Huang PH, Chen JW, Lin CP, et al. Far infra-red therapy promotes ischemia-induced angiogenesis in diabetic mice and restores high glucose-suppressed endothelial progenitor cell functions. Cardiovasc Diabetol 2012;11:99.
Iguchi M, Littmann AE, Chang SH, et al. Heat stress and cardiovascular, hormonal, and heat shock proteins in humans. Journal of athletic training 2012;47:184-90.
Ikeda Y, Biro S, Kamogawa Y, et al. Repeated sauna therapy increases arterial endothelial nitric oxide synthase expression and nitric oxide production in cardiomyopathic hamsters. Circ J 2005;69:722-9.
Kunutsor SK, Laukkanen T, Laukkanen JA. Frequent sauna bathing may reduce the risk of pneumonia in middle-aged Caucasian men: The KIHD prospective cohort study. Respir Med 2017;132:161-3.
Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study. Eur J Epidemiol 2017;32:1107-11.
Laurent H. Control of typhus fever in Finland during World War II. Vesalius 2009;15:71-9.
Li G, Zhang J, Tong X, et al. Heat shock protein 70 inhibits the activity of Influenza A virus ribonucleoprotein and blocks the replication of virus in vitro and in vivo. PLoS One 2011;6:e16546.
Novoselova TV, Margulis BA, Novoselov SS, et al. Treatment with extracellular HSP70/HSC70 protein can reduce polyglutamine toxicity and aggregation. J Neurochem 2005;94:597-606.
Payne J, Nair MP, Ambrus JL, et al. Mild hyperthermia modulates biological activities of interferons. Int J Hyperthermia 2000;16:492-507.
Pilch W, Pokora I, Szygula Z, et al. Effect of a single finnish sauna session on white blood cell profile and cortisol levels in athletes and non-athletes. Journal of human kinetics 2013;39:127-35.
Wang Y, Kelly CG, Singh M, et al. Stimulation of Th1-polarizing cytokines, C-C chemokines, maturation of dendritic cells, and adjuvant function by the peptide binding fragment of heat shock protein 70. J Immunol 2002;169:2422-9.
Wang Y, Whittall T, McGowan E, et al. Identification of stimulating and inhibitory epitopes within the heat shock protein 70 molecule that modulate cytokine production and maturation of dendritic cells. J Immunol 2005;174:3306-16.
Xue J, Fan X, Yu J, et al. Short-Term Heat Shock Affects Host-Virus Interaction in Mice Infected with Highly Pathogenic Avian Influenza Virus H5N1. Frontiers in microbiology 2016;7:924.
Yu SY, Chiu JH, Yang SD, et al. Biological effect of far-infrared therapy on increasing skin microcirculation in rats. Photodermatol Photoimmunol Photomed 2006;22:78-86.