The government has permitted gyms to open from August 5 at a time when daily fresh coronavirus cases in India remain high and the virus is spreading to smaller cities and towns. Zumba classes in a South Korean city and clusters from gyms in Japan have shown how intense physical exertion in closed settings with poor ventilation and for a prolonged period can be a fertile ground for virus spread.
At a time when the number of confirmed novel coronavirus in India is almost 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 gymnasium in areas outside the containment areas to function from August 5 onwards. 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. WHO recommends 30 minutes per day of physical exercise for healthy adults.
But beginning with the cruise ship Diamond Princess and clusters that their origin in churches in South Korea and Singapore, it has been known that prolonged exposure in closed spaces with poor ventilation facilitates virus spread. The spread becomes even more pronounced if such places are also crowded.
Besides fomites (virus contaminated surfaces) and droplet transmission, the World Health Organization had recently acknowledged that aerosol transmission “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”.
Gyms are fertile grounds
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. 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; the force of exhalation will also propel the virus to longer distances.
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.
Examples from outside India
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”.
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.”
Similarly, on March 10, a choir practice by 61 people for 150 minutes at Skagit County, Washington, led to 32 confirmed and 20 probable secondary COVID-19 cases. “Transmission was likely facilitated by close proximity (within 6 feet) during practice and augmented by the act of singing,” notes a study published in Morbidity and Mortality Weekly Report.
Another route of spread that is of concern in gymnasiums is shiny surfaces contaminated with viruses. Since contact with objects of regular use such as dumbbells, weights is inevitable, chances of virus spread is high.
What about yoga
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 asanas that involve deep breathing and exhalation will increase the risk of infection.
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. While wearing masks greatly helps in cutting transmission, care needs to be taken to change the 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 the virus is widely spread in areas even outside the containment zones in large cities, as the sero surveys in Delhi, Ahmedabad and Mumbai have revealed. Also, people with asymptomatic infection form a significant percentage of cases in India.
During the course of the pandemic, it will therefore be prudent to exercise in the open by maintaining physical distancing.