For Runners, Is 15 Feet the New 6 Feet for Social Distancing?

The equivalent social distance during brisk walking was about 15 feet, the researchers also calculated.

Interestingly, they noted little side-to-side flow of air droplets in their model or spillage outside of the athlete’s slipstream. The respiratory droplets clustered in the long, narrow corridor of the athlete’s wake, which was about the width of his shoulders.

The implication of these findings, Dr. Blocken says, is that to keep social distance, runners and walkers should swing well wide when passing other people and not cut back sharply in front of them after passing.

“Be nice and wait awhile before you move back in front of anyone,” Dr. Blocken told me, preferably spacing yourself at least 15 feet or more in front.

Similarly, if you find yourself behind someone while walking or jogging, move to the side until that leading person’s body no longer blocks your view, which should situate you outside of his or her slipstream, Dr. Blocken says.

Bear in mind, though, that this study has considerable limits. It looked at one size of athlete and at the behavior of relatively large respiratory droplets, not the smaller aerosolized type that might linger in the air longer. It also did not include simulations of athletes wearing masks or of the effects of wind. Above all, it did not consider whether respiratory droplets from its imaginary runner contained coronavirus and so cannot tell us whether running or walking closely behind someone increases your risk of being exposed to dangerous germs, only that it increases your risk of being exposed to someone else’s breath.

Reassuringly, “there is no empirical evidence that runners or bikers are a point source of infection,” says Dr. Dean Winslow, a professor of medicine at Stanford University and an infectious disease specialist, who reviewed the new modeling study at my request.

Article source: https://www.nytimes.com/2020/04/15/well/move/running-social-distancing.html