Turning up the heat on COVID-19: heat as a therapeutic intervention

Abstract

Enveloped viruses such as SAR-CoV-2 are sensitive to heat and are destroyed by temperatures tolerable to humans. All mammals use fever to deal with infections and heat has been used throughout human history in the form of hot springs, saunas, hammams, steam-rooms, sweat-lodges, steam inhalations, hot mud and poultices to prevent and treat respiratory infections and enhance health and wellbeing. This paper reviews the evidence for using heat to treat and prevent viral infections and discusses potential cellular, physiological and psychological mechanisms of action. In the initial phase of infection, heat applied to the upper airways can support the immune system’s first line of defence by supporting muco-ciliary clearance and inhibiting or deactivating virions where they first lodge. This may be further enhanced by the inhalation of steam containing essential oils with anti-viral, mucolytic and anxiolytic properties. Heat applied to the whole body can further support the immune system’s second line of defence by mimicking fever and activating innate and acquired immune defences and building physiological resilience. Heat-based treatments also offer psychological benefits and enhanced mental wellness by focusing attention on positive action, enhancing relaxation and sleep, inducing 'forced-mindfulness', and invoking the power of positive thinking and ‘remembered wellness’. Heat is a cheap, convenient and widely accessible therapeutic modality and while no clinical protocols exist for using heat to treat COVID-19, protocols that draw from traditional practices and consider contraindications, adverse effects and infection control measures could be developed and implemented rapidly and inexpensively on a wide scale. While there are significant challenges in implementing heat-based therapies during the current pandemic, these therapies present an opportunity to integrate natural medicine, conventional medicine and traditional wellness practices, and support the wellbeing of both patients and medical staff, while building community resilience and reducing the likelihood and impact of future pandemics.

Spa therapy interventions for post respiratory rehabilitation in COVID-19 subjects: does the review of recent evidence suggest a role?

“…One of the current hypotheses explaining the mechanism of action of inhalation treatments is that inhalations can replace or increase glutathione (GSH), reducing oxidative stress associated with inflammation in lung disorders and production of reactive oxygen species (ROS) (Corradi et al 2012). The heat applied to the whole body during the water immersions could have ulteriorly positive effects on the respiratory system modulating innate and acquired immune defences (Cohen 2020;Masiero et al 2020b;Maccarone et al 2021a;Maccarone et al 2020).…”

“…Spa treatments can also offer psychological benefits and enhance mental wellness, improving relaxation and increasing stress resilience and QoL (Antonelli and Donelli 2020 ; Masiero et al 2020a ; Cohen 2020 ).…”

Innate immunity, inflammation activation and heat-shock protein in COVID-19 pathogenesis

“…Climate could help constrain SARS-CoV-2 ( Araujo and Naimi, 2020 ; Bannister-Tyrrell et al, 2020 ; O'Reilly et al, 2020 ). The restoration of immunoinflammatory balance through hyperthermic treatment has been suggested ( Cohen, 2020 ), and could be a promising treatment option in handling chronic auto-immune disease without the involvement of immunosuppressive approaches ( Tukaj and Kaminski, 2019 ). Hyperthermia-induced heat stress has been shown to mitigate viral infections by a direct inhibition of pathogens, stimulation of both the innate and adaptive transcriptional genes of the immune system and the activation of regulatory processes that dissemble inflammation, and the prevention of cytokine storms that otherwise could cause excessive tissue damage ( Evans et al, 2015 ).…”

“…Heat intervention is one of the oldest forms of microbial control and today remains one of the most common methods for controlling and eradicating pathogens. Control temperatures at 60 °C for 30 min or 65 °C for 15 min or 80 °C for 1 min have been shown to reduced coronavirus infectious by at least 4 fold ( Cohen, 2020 ). However, the therapeutic temperature, humidity, and time required to dissemble SAR-CoV-2 in vivo are yet to be determined.…”

Hydrothermal facilities: essential services in the age of pandemics

“…There is extensive evolutionary, historical, epidemiological, physiological, psychological and clinical evidence supporting the use of heat to treat respiratory viruses as well as treat and prevent other infections and chronic diseases (Cohen, 2020b). Warm humid environments support naso-ciliary clearance, which serves as the immune system's first line of defence against viral respiratory pathogens by trapping viruses, presenting them to the immune system so antibodies can be produced, and then disposing of them before they can cause illness (Fahy & Dickey, 2010).…”