A study conducted by a Belgian-Dutch research team recently went viral after concluding that runners and cyclists were dangerously spreading COVID-19. The 12-page-study warned that their respiratory droplets potentially containing the virus were able to spread further than six feet. Although unpublished and not yet peer reviewed, the study has led to a huge debate over just how dangerous outdoor exercise may be. According to Bert Blocken, one of the study’s researchers, the intention was not to cause panic but to encourage awareness.
According to the study, safe distances are:
65 feet for bike riding at 18 mph
33 feet for running at a 6:44 minutes-per-mile pace
16 feet when walking at a normal pace.
At these distances, the respiratory droplets would have “moved down to the ground” and are therefore no longer a threat of direct exposure. However, the question remains: How likely is it that these particles would make someone sick even if they were exposed?. A recent study published in MedRxiv of 318 outbreaks found that only one transmission occurred outdoors. "We don't yet know what size particles released by an infected person actually contain virus and whether that virus is ‘alive,’ or can still infect others," Professor Linsey Marr, Virginia Tech, via ‘Wired’.
Until more studies can be done, exercise immunologist David Nieman thinks that immune-boosting exercise should continue but in a solitary manner