What is the COVID exposure risk from passing close by someone who is jogging relative to passing close by someone who is walking?

The reason I ask is with regard to going out for exercise, or to run errands: going out early in the morning means passing fewer people, but a larger percentage will be joggers. I'm trying to figure out whether there is an overall risk reduction, whether early morning is safer than the middle of the day.

I have only been able to find answers to adjacent questions:

'Either way, the risk is low outdoors versus indoors.'

Right. But what's the relative risk between these two low-risk outdoor events?

'Ideally, you should keep 4.5m separation from joggers.'

Ideally yes, but as it turns out, sidewalks are not 4.5m wide.

'We don't have enough data to be sure.'

Right. But decisions have to be made based on the best currently available guess. What's the best currently available guess for this? 1.1x? 2x? 5x? 20x?

  • 3
    $\begingroup$ This is a well-worded question, but I imagine there is no research that will give you the precise answer you seek. There are a multitude of variables, each of which is hard to control and provides minimal useful insight: relative viral shedding of a runner v. a walker due to different rates of respiration, the differences in turbulent airflow caused by running v. walking, etc. Moreover, the applicability of results obtained from such a study would be constrained to situations where environmental variables are similar: temperature, humidity, wind, inter-individual variability in viral load $\endgroup$
    – acvill
    Oct 14, 2021 at 14:12
  • $\begingroup$ I agree with @acvill, you might see papers looking at 1 of the variables each, but it would be very hard to do it all in one study. $\endgroup$
    – bob1
    Oct 14, 2021 at 19:16
  • 1
    $\begingroup$ Questions relating to medical advice are off-topic on biology. You might get an answer on SE Medical Sciences, but there are many reputable sources of information on this topic on the Internet (see the Meta article). $\endgroup$
    – David
    Oct 14, 2021 at 20:52
  • $\begingroup$ @acvill Sure, I'm aware there is no precise answer, like I said, I don't seek one, just a best guess to an order of magnitude. $\endgroup$
    – rwallace
    Oct 15, 2021 at 6:51
  • 2
    $\begingroup$ The Meta article is here and was a response to the "plenty…questions" that on covid which were imho not on topic here, and for which this forum is not a place to get the most informed information on a topic for which answers intrinsically constitute medical advice. $\endgroup$
    – David
    Oct 15, 2021 at 7:26


You must log in to answer this question.

Browse other questions tagged .