The numbers are impressive, but experts emphasize that this finding also applies to several other locations.
Scientists already knew that airborne transmission of Covid19 through aerosols — small particles that disperse in the air when you breathe — is significantly greater during indoor physical activity. However, a study published by a team of researchers from the University of Munich shows that during exercise, a person emits 132 times more aerosols per minute than during a moment of rest, which, according to experts, can lead to the creation of energy poles transmission.
The numbers are impressive. When fully immobilized and at rest, we emit an average of 580 particles per minute. However, during highintensity physical exertion, a person can emit up to 76,200 particles per minute to the point of exhaustion.
“These data not only explain the transmission of SARSCoV2 during indoor group exercise, but could also be used to design more targeted mitigation measures for indoor physical activity, such as E.g. physical education classes at school, dance events during weddings or highintensity physical education classes such as spinning,” the study says.
Henning Wackerhage, coauthor of the study and professor of exercise biology at the Technical University of Munich, was surprised by the result of the study, which provides new scientific insights into the number of particles per liter of air during highintensity physical exercise.
“We knew that when you exercise, more air comes out of the human body. But we didn’t know and I didn’t expect that when we exercise a lot there are more particles per liter of air.”
To arrive at this result, the scientists had several people on stationary bikes with a silicone facial mask attached to a plastic container that stores and measures the number of particles, exercising to the point of exhaustion. This “closed loop of air” allowed researchers to get a clearer picture of the number of particles emitted by each of these individuals, eliminating external sources of contamination.
However, the German research team admits that the study has some limitations, starting with the number of people who took part in the sample: only 16 people were tested. Also, none of them were positive for Covid19, but the scientists justify this absence with ethical concerns about potential health risks for the participants.
The scientists also emphasize that although the emission of aerosol particles is one of the main risks for the transmission of SARSCoV2, it is not the only risk, since the infection also depends on the concentration of the virus in the particles released.
The study also shows that the concentrations of aerosol particles in exhaled air vary greatly from person to person. People with better physical preparation emit 85% more particles than other participants. The researchers justify this with the greater need to supply the muscles with oxygen. According to the results of this study, the distribution of the particles does not show any significant differences between men and women.
“It’s not just gyms.” Attention to ventilation
It is no news for specialists that less ventilated spaces and a higher concentration of people pose a higher risk of transmitting diseases such as Covid19. Places where many people sing or dance are indicated by health authorities as potential transmission sites. In that sense, it’s not fair to isolate gyms as the most favorable places for the virus to spread, stresses public health doctor Bernardo Gomes.
“It’s not just the gyms, it’s the physical indoor spaces with no ventilation. The most important thing is ventilation. Indoor air quality must be a priority in the coming years. Places with less ventilation are most conducive to the need to wear a mask,” the public health doctor pointed out, adding that people can look to larger facilities that allow for better airflow and more distance between people.
In addition, gyms are not all the same and using a mask does not solve the problem if we practice some modalities in gyms. The specialist therefore advises you to take into account the times of use and to take care of the ventilation of indoor spaces where you train, especially during periods when the virus is known to circulate with greater intensity.
It is recalled that the average number of infections in Portugal has risen again. This Wednesday, the National Health Institute Doutor Ricardo Jorge (INSA) announced that the number of cases in Portugal has increased from 22,805 to 29,101 daily cases and all regions have a Coronavirus Transmissibility Index (Rt) above the threshold of 1. .
According to INSA’s weekly report on the development of the Covid19 pandemic in the country, the Rt at the national level has fallen from 1.23 to 1.13, but all regions have the average of this indicator above 1 for five days, which means “ indicating an increasing trend” of infections.
The north has an Rt of 1.12, the center of 1.06, Lisbon and Vale do Tejo of 1.20, the Alentejo of 1.09, the Algarve of 1.12, the Azores of 1.21 and Madeira of 1:18, according to the report. The value of the Rt which estimates the number of secondary cases of infection per person carrying the virus has been greater than 1 since April 26.