However, outdoor trails present a unique challenge, as individuals are breathing heavily and potentially even coughing or sneezing along the way. If a second person is following behind, even at what would be considered a “safe” distance for indoor interaction, they would quickly come into contact with particles in the air that could contain the virus.
The scientists ran simulations to determine how serious this risk really is, with virtual exercisers traveling behind one another and the computer tracking the air stream surrounding them. What they found was that you don’t have to be right next to an infected person or even directly behind them to be at risk, depending on the kind of exercise you’re doing.
Based on the simulations and data, the team suggests that individuals who are walking outdoors should maintain a minimum of four meters (13 feet) of separation. Runners and casual bikers should try to stay at least 10 meters apart (33 feet), and fast cyclists should attempt to remain at least 20 meters (66 feet) from others using the same trails. The researchers also note that avoiding the direct path of the person in front of you is vital, even when maintaining these distances.