Heat therapy, an age-old practice, is making waves in modern health discussions, particularly concerning its role in combating respiratory viruses. As the world continues to battle viral infections, understanding the science behind heat therapy and its practical applications can offer significant benefits. This article explores the importance of maintaining a physical barrier against viruses, the ideal temperatures for deactivating viruses, why infections are more common in winter, and how to effectively use heat therapy for health.

The Importance of Physical Barriers Against Viruses

The nasal cavity and sinuses serve as the first line of defense against respiratory viruses. This region maintains a protective mucosal barrier that traps viruses, allowing them to be identified and swept away by the immune system. Additionally, the nasal cavity plays a crucial role in thermoregulation, helping to maintain an optimal temperature that supports the body’s natural defenses. When the mucosal barrier is well-hydrated and functioning correctly, it acts as an effective shield, preventing pathogens from penetrating deeper into the respiratory system.

Ideal Temperature for Deactivating Viruses[1]

The heat sensitivity of viruses is leveraged in the creation of vaccines, where high temperatures are used to deactivate viral components. Research has shown that temperatures between 55 to 65°C (131 to 149°F) for 15 to 30 minutes can effectively deactivate a range of enveloped viruses, including coronaviruses. For instance, studies have found that a test-tube study of coronavirus was completely denatured in 10 minutes at 55°C. Moreover, thermal disinfection at 60°C for 30 minutes, 65°C for 15 minutes, and 80°C for 1 minute was effective in significantly reducing coronavirus infectivity by at least 4 log10. This knowledge underpins the therapeutic use of heat in managing viral infections and suggests practical applications for maintaining health during viral outbreaks.

Why Infections Occur More in Winter

Winter conditions—characterized by limited sunlight, cold air, and low humidity—pose challenges for the nasal cavity. The nasal passages become the coldest part of the body, and the mucosal barrier can dry out and thicken, making it harder to clear. This environment is more conducive to viral penetration and replication. Studies in mice have demonstrated that low humidity (around 20%) can impair antiviral defenses and slow mucociliary clearance, leading to more severe infections compared to higher humidity levels (50%).[2]

Power of Heat to Inactivate Viruses

Heat therapy can be a powerful tool in inactivating viruses before they can establish a foothold in the body. Evidence supports the use of steam inhalation, where warm, moist air helps to clear nasal passages and relieve congestion. The typical protocol includes inhaling steam from hot water while draped with a towel for about 10-15 minutes, two to three times a day.

Enhancing Mucociliary Clearance

Mucociliary clearance is a vital defense mechanism in the human upper and lower airways. Its impairment, whether acquired or genetically determined, predisposes individuals to chronic infections of the nose, paranasal sinuses, and respiratory tree. This mechanism protects the airways against ambient microorganisms, foreign particles, and noxious substances.

The process is both delicate and vigorous, designed to trap and remove particles efficiently. However, many chronic nasal conditions can detrimentally affect mucociliary transport. Acute upper respiratory tract infections can also reduce nasal mucociliary clearance by directly damaging the cilia and altering the rheological properties of nasal secretions.

In a study by Atishkumar[3], it was found that nasal mucociliary clearance significantly improved with steam inhalation of three minutes duration.

Steam Inhalation Method

• Preparation: Boil water and pour it carefully into a bowl.
• Addition of Essential Oils: Add a drop of essential oil, such as eucalyptus oil, to enhance therapeutic effects.
• Inhalation: Drape a towel over your head and the bowl, and slowly bend towards the water until you are about 8 to 12 inches away.
• Duration: Inhale the steam slowly and deeply through the nose for at least two to five minutes. Each session should not exceed 10 to 15 minutes and can be repeated two or three times per day.

Safety Tips

• Supervision: Always supervise children during steam inhalation.
• Temperature Adjustment: Adjust the water temperature to a comfortable level to avoid burns.
• Timing: Use steam inhalation at the first sign of a sniffle to effectively reduce viral load.

Adding Essential Oils

Essential oils have many advantages: small molecules with high lipophilicity, faster onset of action, and virucidal properties at lower toxic concentrations. They are not toxic at therapeutic concentrations and have high vapor pressure. Many can be orally administered, and they exhibit pulmonary exhalation and lower respiratory tropism, making them suitable for deeper delivery in the lungs. These properties make essential oils an excellent addition to steam inhalation therapy.

According to Cohen[4], in the initial phase of infection, heat applied to the upper airways can support the immune system’s first line of defense by enhancing mucociliary clearance and inhibiting or deactivating virions where they first lodge. This effect can be further enhanced by the inhalation of steam containing essential oils with antiviral, mucolytic, and anxiolytic properties.

Ensure Adequate Micronutrient Intake

To bolster the effectiveness of heat therapy, it’s essential to ensure you have enough raw materials, including vitamins and minerals, that your body cannot produce and must obtain from the diet. Micronutrients such as zinc and vitamin D play crucial roles in supporting immune function. For more information on supplements, refer to my supplements page. Other relevant posts to improve wellness include the power of sleep, Slumber Science and my Must Have List for Travel.

Conclusion

Heat therapy, when used correctly, can be a potent ally in preventing and managing viral infections. By maintaining an optimal temperature for deactivating viruses, supporting mucosal barriers, and incorporating essential oils, you can enhance your overall health and resilience against respiratory infections.

For personalized advice on how to integrate heat therapy into your winter wellness routine, I invite you to book a complimentary 20-minute health chat with me here. Let’s work together to keep you healthy and thriving during the cold months.

Stay warm, stay healthy!

References:

[1] Kampf, G., Voss, A., & Scheithauer, S. (2020). Inactivation of coronaviruses by heat. The Journal of hospital infection, 105(2), 348–349. https://doi.org/10.1016/j.jhin.2020.03.025

[2] Kudo, E., Song, E., Yockey, L. J., Rakib, T., Wong, P. W., Homer, R. J., & Iwasaki, A. (2019). 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, 116(22), 10905–10910. https://doi.org/10.1073/pnas.1902840116

[3] Atishkumar B. Gujrathi, Vijayalaxmi Ambulgekar, Ashwini Handal Effect of steam inhalation on nasal mucociliary clearance in normal individuals and nasal disease state. International Journal of Contemporary Medical Research 2016;3(5):1262-1264.

[4] Cohen M. (2020). Turning up the heat on COVID-19: heat as a therapeutic intervention. F1000Research, 9, 292. https://doi.org/10.12688/f1000research.23299.2