Thread by @CorsIAQ

1/ Important tweet by @linseymarr.

Aerobic activities in gyms are a bad idea during this pandemic, and it is difficult to get risk down to what I believe are acceptable levels. Results of a gym simulation I did several months ago are shown here w/ specs next ....

https://twitter.com/linseymarr/status/1316132203504570373

2/ In this simulation I used Infector X in a restaurant in China with a significant outbreak of COVID-19. By analyzing metadata for the restaurant it is possible to ask the following question ... more ...

3/ If infector X is placed in a gym as a staff member, how much volume of virus laden aerosols would someone in the gym inhale relative to those who were infected in Restaurant X? The value "omega" on the vertical axis shows this ratio for different conditions. more ..

4/ For an under-ventilated gym (1/2 of ASHRAE standard 62.1 for the scenario described) the volume intake is nearly twice that for restaurant X. Even for a gym that meets the ASHRAE standard the gym is as infectious to the susceptible patron doing aerobics as Restaurant X.

5/ Even with additional risk reduction layers the ratio is, in my opinion, too high for comfort.

Caveats - this is ONLY for transmission by aerosol particles in the far field and does NOT include close contact or fomites. These other pathways increase risk even more.

6/ Upshot. I used to be a gym rat but have not been back since late February. My model simulations roughly approximate a very busy time at the gym that I miss. Staying healthy and working out is important. Finding ways to do so in a less infectious environment is smart.