At a time when the number of confirmed COVID-19 cases in India is over 1.6 million and the daily growth of cases continues to remain high, the Ministry of Home Affairs on July 29 permitted yoga institutes and gymnasiums in areas outside the containment areas to function from August 5. This, even while other enclosed settings such as cinema halls, bars, auditoriums and assembly halls have been ordered to remain shut.
There is wide agreement that regular moderate intensity exercise is beneficial for immunity. The World Health Organization (WHO) recommends 30 minutes per day of physical exercise for healthy adults.
But, beginning with the cruise ship Diamond Princess and clusters that had their origin in churches in South Korea and Singapore, it has been known that prolonged exposure in closed spaces with poor ventilation facilitates the virus’s spread. The spread becomes even more pronounced if such places are crowded.
Transmission through aerosols
The WHO recently acknowledged that transmission of the virus through aerosols “cannot be ruled” out in “certain closed settings that are crowded, and inadequately ventilated spaces where infected persons spend long periods of time with others”. In addition to being closed spaces with poor ventilation, gymnasiums have another critical factor that will actively facilitate virus spread — deep breathing and exhalation through the mouth by members. The number of droplets and aerosols emitted during huffing and puffing will certainly be manifold higher. While deep breathing is likely to take the tiny droplets and aerosols containing the virus deep inside the lungs, leading to infection, exhalation with force will eject more virus particles into the air and make it travel a long distance.
Given the breathing pattern of people exercising, poor ventilation would mean that the amount of virus present in the room continues to increase with time. People visiting a gymnasium spend at least 30-60 minutes exercising, thus increasing the risk of infection. Cases investigated between January 15 and April 4 in Japan found that many of the COVID-19 clusters were associated with “heavy breathing in close proximity, such as singing at karaoke parties, cheering at clubs, having conversations in bars, and exercising in gymnasiums”.
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In mid-February, in Cheonan city in South Korea, 112 persons who participated in fitness dance (Zumba) classes involving high aerobic intensity at 12 sports facilities were found to be infected with SARS-CoV-2. In a report in the journal Emerging Infectious Disease , the researchers said: “Intense physical exercise in densely populated sports facilities could increase risk for infection. Vigorous exercise in confined spaces should be minimised during outbreaks.”
Another route of spread is through shiny surfaces contaminated with viruses. Since contact with objects of regular use such as dumb bells, weights is inevitable in gyms, chances of virus spread is high.
Investigation in South Korea revealed that unlike the high-intensity Zumba dance classes, pilates (a form of low-impact exercise) and yoga “did not cause the same transmission effects”. However, it is not clear if certain yoga asana s that involve deep breathing and exhalation will increase the risk of infection.
Maintaining distancing
One way to limit the risk of virus spread is by limiting the number of patrons who can use the gymnasium at any point of time, maintaining physical distancing, vastly improving ventilation, and through regular and periodic cleaning of all equipment. Care also needs to be taken to change masks the moment they get wet.
In recent weeks, the virus has spread from large cities to tier-2, tier-3 cities and towns, and its spread is also being observed in areas even outside the containment zones in large cities, as the sero surveys in Delhi, Ahmedabad and Mumbai have revealed. Hence, during the course of the pandemic, it would be prudent to exercise in the open by maintaining physical distancing.
prasad.ravindranath@thehindu.co.in
