Nicholas B. Tiller

The blog that unifies scientific skepticism, critical-thinking, health & fitness, and the exercise sciences

  • Nicholas B. Tiller Ph.D.

#47: Exercise in the age of COVID; a conversation with Harry Rossiter

[This article was originally published in "Reach" - The Lundquist Institute's quarterly magazine:]

The COVID-19 pandemic continues to have a profound impact on our activity levels. It could be that working from home and/or self-isolation has reduced the amount of walking you normally do, or perhaps the closure of sports clubs has forced you to conjure new and inventive ways of achieving your daily exercise. Regardless of your usual level of activity, it’s likely that COVID-19 mitigation strategies (e.g., wearing face coverings, physical distancing, and lockdowns) has had a dramatic impact. This article captures a conversation between Lundquist investigators, Drs. Harry Rossiter and Nick Tiller, in which they discuss some important considerations for exercise in the age of COVID-19.

Nick: I think a good place to start is to reiterate the importance of regular exercise; not just for navigating the pandemic, but for maintaining general whole-body health. Why is it so important to be physically active?

Harry: Physical inactivity is an “actual cause” of chronic disease; it is one of the 3 most important things we can chose do to support a healthy life (along with good nutrition and not smoking). There’s overwhelming evidence that regular physical activity (including structured exercise) helps prevent numerous non-communicable diseases including cardiovascular disease, type II diabetes, and certain cancers. Exercise is also important for good mental health. The social component shouldn’t be overlooked, although this is clearly more difficult in the current climate where good physical distancing is paramount.

Nick: Regular exercise is so important for good physical and mental health. I know of many people who participate in online group training sessions which are great for improving physical health, but also partially replicate the social component of an exercise class. It’s worth noting that many patients with underlying health conditions are on regular medication to manage their disease: to improve cardiovascular health, lower blood pressure, lower cholesterol, increased insulin sensitivity and glucose tolerance, etc. Exercise can accomplish all of these things simultaneously. If there were a drug that could achieve that, its creator would be worthy of a Nobel Prize.

Harry: If only an “exercise pill” were not science fiction! If we know exercise is so important, then why do you think so few people meet the recommended 150 minutes of moderate-to-vigorous physical activity per week?

Nick: People struggle to forge new habits, especially when they don’t see immediate benefits. Humans are programmed to seek-out the “quick fixes” and rapid results; hence the popularity of nutritional supplements and fad diets even though neither are as effective as a structured exercise program and healthy eating. Chronic lifestyle interventions are difficult, and making them a habit takes time and perseverance, but it’s really worth it. So how can people go about beginning a new exercise regimen during the pandemic? Also, is there a risk that exercise will compromise immunity or increase the risk of catching the virus?

Harry: Increasing physical fitness through exercise training is beneficial for immune function, which may help reduce severe disease if one were to catch the virus; hence the importance of regular exercise. Similarly, physical inactivity is associated with chronic inflammation and a less effective immune system. Having said that, a single bout of vigorous exercise or “overtraining” can temporarily affect the immune system and increase susceptibility to infection. Data strongly demonstrate that a bout of vigorous endurance exercise - such running a half marathon - results in a temporarily (non-pathogenic) increased risk of upper-respiratory tract infection (URTI). For this reason, it may be a good idea to avoid marathons and triathlons for a while. It’s also of paramount importance to avoid the crowds that may gather at these events.

Nick: So, is it true that the act of exercising around other people has inherent risks in terms of virus transmission?

Harry: Well, SARS-CoV-2 is an airborne virus. In general, I think there has been poor education on precisely what this means. It means that SARS-CoV-2 is primarily transmitted through the air as droplets and tiny particles that are secreted from the nose and mouth of an infected person. Coughs, sneezes, lung function testing, and exercise are all considered to be “aerosol-generating” events because the individual generates particles that are sufficiently small and light to remain suspended in the air for long periods, travel beyond 6 ft from the source, and penetrate or circumnavigate surgical masks. So, yes, exercising close to an infected person–especially in a confined space such as an indoor gym–can increase the risk of infection.

Nick: So, to minimize the risk of infection when exercising, we should be following the normal public health guidance: exercise outdoors if possible, avoid exercising in groups and, of course, wear a facemask.

Harry: Exactly. Facemasks are considered one of our primary tools in combating transmission. How do you feel when you exercise with a mask? Some people have expressed concern that this might be harmful.

Nick: They have, but the concerns are unfounded. There’s good evidence now showing that wearing a facemask during exercise is safe. In fact, two review articles were recently published in good journals by respiratory experts. After collating the studies, both articles independently concluded that exercising with a mask does not have any health implications and is likely safe even at higher exercise intensities, albeit slightly uncomfortable for the wearer. Having said that, high intensity interval training with a sealed N95 is not much fun. Instead, wear a thick cloth or surgical mask during exercise and prioritize lower-intensity activity. It goes without saying that anyone who is considering changing or adding a new exercise regime to their schedule should have a discussion with their primary physician beforehand.

Harry: OK, so we’ve established that regular exercise is important for good physical and mental health, and that facemasks aren’t a barrier to exercise. As the COVID-19 vaccine is rolled out throughout the world, are there any concerns regarding how exercise might affect how people will respond to the vaccine?

Nick: Studies in the general population have shown heightened rates of vaccine efficacy (better effects), with an increased antibody titer, in individuals who did moderate intensity exercise before vaccination. If anything, regular exercise might improve the immune response following vaccination. However, the data aren’t conclusive. One consideration is that some individuals do experience transient side effects following vaccine, including lethargy, muscle aches, and mild fever, and so it’s a good idea to avoid exercise during this time.