According to recent University of Bristol-led research, high-intensity exercise results in much more respiratory particles than speaking but vigorous exercise does not.
The study, which was published in Communications Medicine, is the first to assess the amount of inhaled aerosols produced during exercise in order to assess the possibility of SARS-CoV-2 airborne viral transmission in indoor exercise facilities and during team sports and physical activities.
SARS-CoV-2 is thought to spread mostly through inhalation of infected aerosol. To quantify the size and concentration of expelled particles (up to 20 m diameter), which are created in our respiratory tracts and breathed out, during intense and high-intensity exercise, a UK-wide collaborative team of physicians and academics conducted the first study of its type.
Using a cardiopulmonary exercise test (CPET), 25 healthy people were selected to participate in four different activities on a cycle ergometer: breathing at rest, speaking at a regular conversational volume, strenuous activity, and high-intensity exercise.
In order to detect airflow and send any particles released from the participants’ mouths and noses to a particle counter, they inhaled into a specially designed mask. The researchers were able to clearly distinguish the particles produced by the participants since the orthopedic operating room provided a “zero aerosol background” for the experiments.
COVID-19 has profoundly impacted sports and exercise, and this study provides a comprehensive analysis of the mass emission rates of aerosol that can potentially carry infectious virus produced from an individual during exercise. Our research has shown that the likely amount of virus that someone can exhale in small aerosol particles when exercising is comparable to when someone speaks at a conversational volume. The most effective way to reduce risk is to ensure spaces are appropriately ventilated to reduce the risk of airborne transmission.
Jonathan Reid
The researchers discovered that the size of airborne particles released during intense activity was comparable to a person’s resting breathing. However, it was shown that the pace at which people exhale aerosol mass while engaging in severe activity is comparable to speaking at a conversational volume.
Jonathan Reid, Director of ESPRC Centre for Doctoral Training in Aerosol Science and Professor of Physical Chemistry in the School of Chemistry at the University of Bristol and scientific lead on the paper, said: “COVID-19 has profoundly impacted sports and exercise, and this study provides a comprehensive analysis of the mass emission rates of aerosol that can potentially carry infectious virus produced from an individual during exercise. Our research has shown that the likely amount of virus that someone can exhale in small aerosol particles when exercising is comparable to when someone speaks at a conversational volume. The most effective way to reduce risk is to ensure spaces are appropriately ventilated to reduce the risk of airborne transmission.”
