Joggers and cyclists should wear masks – here’s why

England is deep into its third lockdown, but the daily toll of new COVID cases and deaths remains extremely high. As Chris Whitty, the country’s chief medical officer, recently said, there is still a long way to go to bring the pandemic under control.

Masks, which when worn correctly are very effective in reducing transmission, are already mandatory in indoor public places in the UK. There is talk of making them mandatory in certain outdoor environments, as is currently the case in Spain. Perhaps the UK should follow France and force people who jog or cycle to wear masks if they are unable to maintain a physical distance from pedestrians.

There are many arguments against such a measure. The risk of transmitting the coronavirus outdoors is an order of magnitude lower than indoors, according to a study that has not yet been published in a scientific journal. Outdoor exercise is one of the few freedoms still available to the British. When jogging or cycling, contact tends to be rare and fleeting, so it would not meet the UK’s official definition of ‘close contact’ requiring 15 minutes to be spent within two meters – although this period can now be noted as a series of shorter encounters throughout a day.

The World Health Organization (WHO) is adamant that: “People should NOT wear a mask when exercising, as masks can reduce the ability to breathe comfortably”; and “Sweat can make the mask wet more quickly, which makes it difficult to breathe and promotes the growth of microorganisms.” The WHO recommendation is to maintain at least one meter of physical distance from others.

But there are also strong arguments for challenging WHO’s advice. The main one is that the NHS is really overwhelmed for the first time in its 70-year history due to the increase in COVID hospital admissions. All possible measures should be taken to reduce these numbers.

More than half of all cases of COVID are acquired from people who have no symptoms at the time they pass it on. The 15 minute rule for close contact is arbitrary (based on custom and practice rather than empirical evidence). The one-meter or two-meter distance rules (which stem as much from business models of lost productivity as from scientific evidence of protection) don’t mean that if people stay at those distances, they’re safe. The rules only mean that people farther away are less likely to infect each other.

Ethical argument

Masks work primarily by protecting other people. Pedestrians passed by a relatively young and fit jogger or cyclist include those who are older or more vulnerable to COVID and its complications. If there is a risk of transmission, there is surely an ethical argument to hide.

The exhaled breath of a person who exercises vigorously has a different composition and aerodynamic properties than of someone who is not. As we all know, a passing jogger breathes heavily, generating exhales with a much higher momentum than when breathing at rest.

In cold weather, clouds of moisture laden air become visible when the jogger exhales – and these clouds spread much further than those exhaled by walkers. Formal studies of the aerodynamics of breathing confirm that heavy respirators emit turbulent clouds of gas in which droplets and microdroplets of varying sizes are suspended, some of which are carried considerably farther than two meters.

Several variants of the coronavirus have been shown to be more transmissible than the original virus. Because each infected person is now likely to infect between 30% and 60% more people than before, an unlucky inhalation near a passing jogger – itself a rare possibility – is now much more likely to ’cause a growing series of secondary cases. , one or more of which could be fatal.

Contrary to some sources of information, there is no evidence that occasional jogging in a mask (as opposed to vigorous exercise performed in a ventilator fitted for the specific purpose of pushing one’s physiology to extremes) results in metabolic damage. important. And in particular, the oxygen levels in the blood are not reduced when exercising with a cloth or medical mask.

The WHO is correct that masks may reduce the ability to breathe comfortably, although masks made of materials (such as multi-layered muslin or a muslin-flannel combination) that have low strength but high filtration capacity will reduce this issue. Varying your exercise route may allow the mask to be safely removed for certain sections – for example, when you reach a park. A wet mask can be replaced with a spare dry mask transported for this purpose.

A final reason to wear masks when exercising near others is the message of social solidarity that it conveys. The masked jogger or cyclist says both “the pandemic is still very serious” and “your safety is more important than my comfort or my lap time”. Instead of aggressive confrontations between the maskless sportsmen and the frightened walkers (which sometimes involves the potentially contagious act of screaming at close range), we might expect both parties to exchange a silent wave as they peacefully pass. .

Almost all research on masks and exercise has been carried out in specialized laboratories. My own team is about to undertake a more pragmatic randomized controlled trial of the impact of different types of masks on exercise capacity, comfort, and physiological markers in people exercising outdoors. We hope to report the results of this study later this year.