The Benefits of Hydro-Thermal Therapies for Building Health and Resilience

By Professor Marc Cohen, Board Member of the Global Wellness Summit, Co-founder of the Bathe the World Foundation and Founder of the Extreme Wellness Institute.

Hydro-thermal therapies such as hot baths, cold plunges, saunas, steambaths and mud-wraps improve public health, reduce the risk of chronic disease and boost the immune system’s ability to resist viral infections. Hydro-thermal therapies also confer psychological benefits and improve sleep, relieve stress, and foster interpersonal connection and connection with nature.

Hydro-thermal Therapies Can Enhance Health and Wellbeing and Help Treat and Prevent Viral Infections

  • The benefits of hydrothermal therapies have been known for thousands of years and have been shown to be effective for disease prevention and health promotion [1-3].
  • Hydrothermal therapies such as saunas, steam rooms, hot baths, balneotherapy, pelotherapy etc are backed by historical, epidemiological, anecdotal, clinical and randomized controlled-trial evidence that attest to their safety and efficacy[4].
  • There is evidence to show hydro-thermal therapies such as bathing [5], balneotherapy [6], sauna bathing [7], massage [8] and healing touch [9] are safe and effective in the treatment and prevention of many chronic diseases [10].

Hydrothermal Therapies Inhibit Viral Virulence

  • Enveloped viruses such as coronaviruses are most active in cool dry conditions, which are associated with increased occurrence of respiratory tract infections [18], including infections with SARS-CoV [19] and SAR-CoV-2 [20, 21].
  • Warm humid environments reduce airborne droplet spread inhibit transmission of respiratory viruses and humidity of around 50% leads to slower infection and less severe illness [22]
  • Air quality is enhanced at hot springs and thermal water inhalation is able to modulate and enhance systemic immune responses [23].

Hydrothermal Bathing Supports Host Resistance

  • Raising body temperature through exposure to external heat is an evolutionary that has been preserved for over 600 million years and is used by fish insects, reptiles, birds, and mammals for controlling viral infections [24].
  • 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 [25].
  • Recent evidence shows balneotherapy and aquatic therapy improves respiratory function and helps prevent and treat respiratory diseases [27, 28].

Hydrothermal Therapies Build Community Resilience

  • Bathing is essential for good health and investments in clean water initiatives that provide access to optimum bathing facilities support individual, community and global health.
  • Hydrothermal treatments provide psychological benefits that are difficult to overstate.These benefits can help overcome the trauma and feelings of helplessness from forced confinement and uncertain economic and social circumstances, and include improved sleep, reduction of stress and anxiety, connection with nature and social connection [29-31].
  • Supporting hydrothermal bathing as a regular lifestyle activity builds community resilience, provides medical personnel with respite, and contributes to a culture of wellness.

Common Sense Safety Principles

Heat is a powerful force and like any powerful intervention, has the potential to either harm or help. Common sense safety precautions when using heat include:

  • Drink: Ensure your stay hydrated with a good quality water.
  • Take care: Avoid burns or scalds near sources of heat and sudden changes in posture that could lead to dizziness or fainting;
  • Know your limits: Heat tolerance varies widely between individuals and within the same individual at different times. Use your comfort level as a guide to exposure and don’t go beyond the point of being ‘comfortably uncomfortable’.
  • Be aware: Tune into your senses, monitor your tolerance and enjoy heat-induced forced mindfulness’. Avoid extremes of temperature when under the influence of alcohol or drugs that impair your judgement;
  • Rest: Alternate exposure to hot or cold with relaxation and re-balancing periods.

Spend at least as much time resting and coming back into physiological balance as you spend in extremes of temperature.

To learn more about water therapies with Prof Marc Cohen check out our new short course Helping Your Patients Reduce Stress. This course explores the impact of stress and the scientific evidence base of some of the therapies that may be able to alleviate stress, including mindfulness, breathwork, CBT, hypnotherapy, yoga and sound therapy.

This article is a partial extract of a position paper prepared by Prof Marc Cohen called Hydro-Thermal Therapies Are Essential for Building Health, Safety and Resilience in the Age of Pandemics



1. Galvez, I., S. Torres-Piles, and E. Ortega-Rincon, Balneotherapy, Immune System, and Stress Response: A Hormetic Strategy? Int J Mol Sci, 2018. 19(6).

2. Agishi, Y., Clinical Usefulness of Long-Term Thermohydrotherapy (Balneotherapy), in Thermotherapy for Neoplasia, Inflammation, and Pain, M. Kosaka, et al., Editors. 2001, Springer Japan: Tokyo. p. 486-494.

3. Nasermoaddeli, A. and S. Kagamimori, Balneotherapy in medicine: A review. Environmental health and preventive medicine, 2005. 10(4): p. 171-179.

4. Hyperthermia in Humans Enhances Interferon-γ Synthesis and Alters the Peripheral Lymphocyte Population. Journal of Interferon Research, 1988. 8(2): p. 143-150.

5. An, J., I. Lee, and Y. Yi, The Thermal Effects of Water Immersion on Health Outcomes: An Integrative Review. Int J Environ Res Public Health, 2019. 16(7).

6. Antonelli, M. and D. Donelli, Effects of balneotherapy and spa therapy on levels of cortisol as a stress biomarker: a systematic review. International Journal of Biometeorology, 2018. 62(6): p. 913-924.

7. Hussain, J. and M. Cohen, Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review. Evid Based Complement Alternat Med, 2018. 2018: p. 1857413.

8. Ng Kenny, C., M. , The Effectiveness of Massage Therapy A Summary of Evidence Based Research 2012, Australian Association of Massage Therapists Melbourne Australia.

9. Wardell, D.W. and K.F. Weymouth, Review of studies of healing touch. J Nurs Scholarsh, 2004. 36(2): p. 147-54.

10. Bender, T., et al., Evidence-based hydro- and balneotherapy in Hungary–a systematic review and meta-analysis. Int J Biometeorol, 2014. 58(3): p. 311-23.

11. Lelie, P.N., H.W. Reesink, and C.J. Lucas, Inactivation of 12 viruses by heating steps applied during manufacture of a hepatitis B vaccine. J Med Virol, 1987. 23(3): p. 297-301.

12. Hu, L., et al., Biophysical characterization and conformational stability of Ebola and Marburg virus-like particles. J Pharm Sci, 2011. 100(12): p. 5156-73.

13. Duan, S.M., et al., Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation. Biomed Environ Sci, 2003. 16(3): p.246-55.

14. WHO Report, First data on stability and resistance of SARS coronavirus compiled by members of WHO laboratory network. 2003, WHO Multi-center Collaborative Network on SARS Diagnosis.

15. Darnell, M.E.R., et al., Inactivation of the coronavirus that induces severe acute respiratory syndrome, SARS-CoV. Journal of Virological Methods, 2004. 121(1): p. 85-91.

16. Kampf, G., A. Voss, and S. Scheithauer, Inactivation of coronaviruses by heat. Journal of Hospital Infection, 2020.

17. Centres For Disease Control, COVIDView (May 1st). 2020, Centres For Disease Control.

18. Makinen, T.M., et al., Cold temperature and low humidity are associated with increased occurrence of respiratory tract infections. Respir Med, 2009. 103(3): p.456-62.

19. Chan, K.H., et al., The Effects of Temperature and Relative Humidity on the Viability of the SARS Coronavirus. Adv Virol, 2011. 2011: p. 734690.

20. Wang, J., Tang, K., Feng, K., Lv, W., High Temperature and High Humidity Reduce the Transmission of COVID-19 2020.

21. Sajadi, M.M., Habibzadeh, P., Vintzeleos, A., Shokouhi, S., Miralles-Wilhellm, F.,Amosroso, A., Temperature and Latitude Analysis to Predict Potential Spread and Seasonality for COVID-19. 2020:

22. Kudo, E., et al., Low ambient humidity impairs barrier function and innate resistance against influenza infection. Proceedings of the National Academy of Sciences, 2019. 116(22): p. 10905-10910.

23. Magrone, T., et al., Effects of thermal water inhalation in chronic upper respiratory tract infections in elderly and young patients. Immunity & ageing : I & A, 2016. 13: p.18-18.

24. Evans, S.S., E.A. Repasky, and D.T. Fisher, Fever and the thermal regulation of immunity: the immune system feels the heat. Nat Rev Immunol, 2015. 15(6): p. 335-49.

25. Cohen, M., Turning up the heat on COVID-19: heat as a therapeutic intervention [version 2; peer review: 2 approved]. F1000Research, 2020. 9(292).

26. Fahy, J.V. and B.F. Dickey, Airway mucus function and dysfunction. The New England journal of medicine, 2010. 363(23): p. 2233-2247.

27. Choukroun, M.L., C. Kays, and P. Varene, Effects of water temperature on pulmonary volumes in immersed human subjects. Respir Physiol, 1989. 75(3): p. 255-65.

28. Karampitsakos, T., Dimakou, K., & Bouros, D.,, Role of aquatic therapy and speleotherapy as complementary therapies in the respiratory system. Pneumon, 2016. 29: p. 269-273.

29. Clark-Kennedy, J. and M. Cohen, Indulgence or therapy? Exploring the characteristics, motivations and experiences of hot springs bathers in Victoria, Australia. Asia Pacific Journal of Tourism Research, 2017. 22(5): p. 501-511.

30. Rapoliene, L., A. Razbadauskas, and A. Jurgelenas, The reduction of distress using therapeutic geothermal water procedures in a randomized controlled clinical trial. Adv Prev Med, 2015. 2015: p. 749417.

31. Dubois, O., et al., Balneotherapy versus paroxetine in the treatment of generalized anxiety disorder. Complement Ther Med, 2010. 18(1): p. 1-7.