Monday, June 1, 2020
Bicycling or Hiking? Stay Out of the Slipstream
The slipstream study isn’t set in concrete, but it couldn’t hurt to err on the side of caution, staying some distance behind your bicycling buddies.
Tuesday, April 28, 2020


Drafting behind your bicycle buddies might not be a good idea in the summer of the coronavirus.

The reason? Slipstream.

A study done by the research universities KU Leuven of Belgium and TU Eindhoven of the Netherlands purports that allowing six feet between yourself and another person might be perfectly effective when you’re standing still inside or outside with just a slight breeze.

Paul Ries added just one new case Monday to "The Curve" showing the number of confirmed and probable cases in Blaine County.

But go for a walk, run or bike ride and, they say, your particles stream behind you in the air. And it’s possible that anyone just behind you is likely to move through this cloud of droplets.

They do not move along when you’re running or cycling. They come to a standstill and you leave them behind. And when you run through that cloud they can still land on your clothing, said Belgian Professor Bert Blocken, of the Eindhoven University of Technology

The study has yet to be formally reviewed for publication in an academic journal, which would give other researchers a chance to make sure the study didn’t arrive at any false conclusions. And computer simulations can be flawed when it comes to microbiology.

But wind tunnel experiments have also shown how aerosolized water vapor can travel from people exhaling while walking, running and biking, leaving a water vapor cloud that extends beyond six feet.

The study by Leuven and Eindhoven used a computer simulation to show that people who sneeze or cough spread droplets with a bigger force. But people who just breathe will leave particles behind. It’s reasonable to presume people who breathe heavily leave more droplets behind than those with shallow breathing.

The good news: Other studies determine that there seems to be less risk when you’re walking, running or even bicycling side by side, as the droplets land behind both people.

In addition, a slipstream has a narrow width so the risk drops significantly when the runner behind positions himself diagonally behind the runner in front.

If you do find yourself on the hiking trail behind someone who is walking quickly, try to remain at least 15 feet behind. Allow 33 feet for runners and slow bicyclists and 65 feet for cyclists who appear to be chasing after an imaginary Tour de France pack.

As for passing someone? Try to stay in a different lane at a considerable distance for at least 65 feet. You could also hold your breath as you pass.

If you want to try your own experiment, go out on the bike path and wait for someone wearing perfume to pass. It may take a while as not many people in this valley wear perfume. But you can definitely smell the perfume long after the person has passed. And, chances are viruses can linger in the air just like perfume or cigarette smoke.

The online platform medRxiv says that only one or 300-plus coronavirus outbreaks in China this year is believed to have happened through outdoors transmission. Most occurred in homes.

For now, if you want to be extra cautious: Back off!

Or, ride and run solo. Wear a bandana while running or biking. And, above all, if you feel sick, stay home.


A Massachusetts Institute of Technology researcher has found that a virus transmitted by a sneeze indoors can travel as far as 27 feet and remain floating in the air for hours.

And a study of an intensive care unit ward in Wuhan, China, published by the Centers for Disease Control found aerosolized COVID-19 virus up to 13 feet away on computer mouse pads and trash cans.


Idaho gained 20 new cases of coronavirus on Monday for a total of 1,917. The state has had 58 deaths from the virus. The two new deaths came in Nez Perce County, which leads its 43 counterparts with 15 deaths.

More than 19,000 Idahoans have been tested so far.

Blaine County now has 493 cases, with one new case being confirmed on Monday. Of that number 479 are no longer being monitored.



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