Finnish sauna and COVID-19

Abstract: Le Infezioni in Medicina, n. 1, 160-162, 2021 160 LETTERS TO THE EDITOR Finnish sauna and COVID-19 Setor K. Kunutsor1,2, Carl J. Lavie3, Jari A. Laukkanen4,5,6 National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol, Bristol, UK; 2 Musculoskeletal Research Unit, Translational Health Sciences, Bristol Medical School, University of Bristol, Learning & Research Building (Level 1), Southmead Hospital, Bristol, UK; 3 John Ochsner Heart and Vascular Institute, Ochsner Clinical School-the University of Queensland School of Medicine, New Orleans, Louisiana, USA; 4 Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; 5 Institute of Clinical Medicine, Department of Medicine, University of Eastern Finland, Kuopio, Finland; 6 Central Finland Health Care District Hospital District, Department of Medicine, Jyväskylä, Finland District, Jyväskylä, Finland 1 Dear Editor Over the last 11 months, coronavirus disease 2019 (COVID-19) -caused by Severe Acute Respiratory Syndrome Coronavirus 2, SARS CoV-2- has had devastating effects on the world, with substantial morbidity and mortality. In a desperate search to find effective preventive and curative therapies for COVID-19, several recommendations entered the spotlight. Some preventive measures that were proposed included vitamins D and C supplementation, given their ability to enhance innate immunity [1, 2]. There have been anecdotal reports that exposing oneself to high temperatures can prevent COVID-19. During the summer, many countries witnessed a decrease in transmission of COVID-19 as well as decreases in severe illness and deaths associated with the disease. This letter was driven by the fact that our research group has been inundated with numerous enquiries on whether heat exposure from saunas may be effective in combating COVID-19. Our primary research focus has been the role of passive heat therapy (using Finnish sauna) in the prevention of cardiovascular disease (CVD) and other non-communicable diseases [3]. Evidence suggests that high temperatures can reduce the transmission of influenza and the Severe Acute Respiratory Syndrome (SARS) viruses, as well as COVID-19 virus [4-6]. SARS-CoV-2 is the seventh member of the family Corresponding author Setor K. Kunutsor E-mail address: skk31@cantab.net of coronaviruses that infect humans. The coronaviruses are enveloped viruses which can remain active in cool dry conditions, but are destroyed by temperatures tolerable to humans; it has been shown that temperatures ranging from 60 to 80°C for 30 to 1 min duration, respectively, could inactivate the coronaviruses [7]. In a study that evaluated the stability of the virus in different environmental conditions, Chin and colleagues demonstrated that SARS-CoV-2 was highly stable at 4°C, but sensitive to heat [8]. In virus media incubated for 14 days, infectivity of the virus was still high at a temperature of 4°C on day 14, whereas when the incubation temperature was increased to 70°C, the virus was inactivated within 5 mins. In a multicity study conducted in China to determine the impact of meteorological factors on COVID-19 transmission, it was observed that weather conditions associated with low temperature, mild diurnal temperature range and low humidity, were more likely to favour the transmission of COVID-19 [4]. Passive heat therapy is..