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Holding your breath on runs could help keep you from getting sick, study finds

Holding your breath for five seconds after coming face-to-face with someone on a run could help cut your risk of catching COVID-19, the flu and other airborne illnesses, according to a new study out of Japan.

The finding comes from researchers at the University of Tsukuba, who investigated the link between aerosol dynamics and viral exposure risk during movement and face-to-face interactions.

For the study, researchers used a full-scale mobile mannequin that was propelled at different speeds to simulate walking (5 km/h), jogging (10 km/h), running (15 km/h) and sprinting (20 km/h), and used specialized equipment to visualize the “flow field” of aerosol particles from exhaled air. The researchers compared the differences between aerodynamic characteristics with and without ventilation and their effects on the risk of exposure to viruses.

They found that, regardless of pace and whether the face-to-face encounter happens in a non-ventilated or fully ventilated area (such as outdoors), the risk of viral airborne transmission remains highest within five seconds of a face-to-face encounter, and then falls off sharply.

Although this five-second window of peak transmissibility after face-to-face contact holds true whether walking or sprinting, pace may play a factor in the risk of transmissibility. Researchers found that as speed increases, especially in a non-ventilated area, the number of aerosol particles a runner is exposed to after an interaction decreases.

Of note to runners worried about contracting an illness during exercise are the three “risk-hedging behaviours” the researchers say “may greatly reduce the risk of viral exposure” during face-to-face encounters during runs.

Among their recommendations is “interrupting … inhalation” during the five seconds of peak transmissibility risk that follows a face-to-face encounter, either by holding your breath or exhaling for five seconds after passing someone on your run.

The researchers also recommend maintaining a distance of at least one metre from anyone coming at you from the opposite direction, and positioning yourself upwind from the other person, when possible.

“These actions are particularly effective during the critical (five-second) interaction period,” the researchers write. “Based on our findings, this study has implications for reducing aerosol-mediated transmission