“As mechanical engineers who consult on heating, ventilating, and air conditioning (HVAC) systems, we’ve been closely following the evolving body of knowledge about how the SARS-CoV-2 novel coronavirus (the virus which causes COVID-19) spreads through the air. We thought some folks might be interested to know some of what we’ve learned, and how that’s affecting our thoughts on returning to the gym.”
Cara and Sarah are guest bloggers, fit feminists, and mechanical engineers thinking about when it’s safe to go back to the gym. This was the most read post of the month by a long shot.
Cate interviews Dr. Michael Gardam, an infectious disease specialist and Chief of Staff at Humber River Hospital in Toronto, and a frequent voice on CBC and Global TV to make sense of some of the tangled messaging about COVID-19 and outdoor exercise.
Cate puts on her social scientist hat and listens to the bloggers talk about going back to the gym.
“In most of Canada, gyms aren’t open yet, but clearly, they have their feet in the blocks waiting for the starter pistol. It’s understandable — fitness studios depend on class and member revenue to survive, and most have hefty investments in space and equipment. We had an animated conversation about this among the bloggers about our own comfort, and realized that most gym managers/ owners are not likely to err on the side of caution — they want to open, and as soon as they are permitted, they will be looking to their members to tell them what will work for them. So what DO we feel safe doing? I captured the key themes from a few of our bloggers.”
Susan reminds us that it’s okay not to be okay with all of this.
“You weren’t built for this and you don’t have to say it’s okay, or good enough, or the same, or tolerable. Day after day, your nervous system seeks and searches and wonders when it can dare to be soothed, when it is allowed to declare a need to just be with, without being accused of. . .something. . .bad. It doesn’t understand and that’s okay, you weren’t built for this.”
Ottawa Centre MP Catherine McKenna biked to work in a dress, posted a pic on Twitter for Bike to Work Day, lots of people hated it, but feminists and cyclists of Twitter came to the rescue. Sam chimed in and also blogged about it.
This #BikeToWorkDay, let's continue to promote cycling and other forms of active transportation for smarter, and cleaner communities. 🚴🏻♀️🚴🏿♂️🚴
CW: discussion of research related to body weight, BMI, and weight gain.
While the rest of us have been busy baking bread at home, nutrition researchers have been hard at work keeping dessert science going strong. They’ve been thinking and plotting and measuring and parceling out various amounts of dessert items to various sizes of people, then watching them closely to see what happens.
(side note: if you’re not familiar with the references in this meme, you’re in for a sweet treat! Start here, then go here. Important: this is not to be confused with the “mikshake duck” meme, which I just learned about one minute ago.)
Back to the meme at hand: that’s not their research question (better to leave it to the “directions for future studies” section). Here’s what they wanted to know:
Prevailing models of obesity posit that hedonic signals override homeostatic mechanisms to promote overeating in today’s food environment.,,Here we define hedonic as orosensory pleasure experienced during eating and set out to test whether there is a relationship between adiposity and the perceived pleasure of a palatable and energy-dense milkshake.
non-science-journal version: they want to know if people’s body weights have an effect on how yummy milkshake consumption seems to them. What they are actually looking for is whether larger people report yummier milkshake drinking experiences (which they think might partly explain their larger sizes). That’s what these scientists are really up to.
What’s next? The researchers set up their test group: 110 people with BMI 19.3–51.2. They asked them to arrive neither hungry nor full, and to have not eaten for at least one hour. The participants came, and waited.
Please note that this study took place before pandemic social distancing protocols were instituted. Otherwise, group size would be strictly limited.
Back to the study: I can’t tell you about the exact methods because even with my awesome library access I can’t get the full article yet. But: the researchers measured hunger before milkshake consumption and also recorded how much the participants said they liked and wanted the milkshake (during consumption).
Finally, we get the results! Here’s what the article says:
We identified a significant association between ratings of hunger and milkshake liking and wanting. By contrast, we found no evidence for a relationship between any measure of adiposity and ratings of milkshake liking, wanting, or intensity.
We conclude that adiposity is not associated with the pleasure experienced during consumption of our energy-dense and palatable milkshakes. Our results provide further evidence against the hypothesis that heightened hedonic signals drive weight gain.
Uh oh! The nutrition scientists got a negative result! They found that body weight had no effect at all on how pleasurable people said their milkshakes were. Keanu pretty much sums it up:
Yes, the study did find a correlation between hunger levels pre-consumption and reported pleasure during consumption. But no one doubted that. And yes, it’s a good thing when scientists get and publish a report on failure to find correlations.
This study gives us a glimpse of something very interesting and a bit worrisome to me, as a fat woman and a health ethics researcher: medical research spends a lot of time and effort searching for causal factors involved in body weight and weight gain that are located in individual persons’ actions, psychological makeups and personal habits. Are fatter people fatter because of something they are doing or feeling or attracted to?
These scientific questions make me uneasy about what may be underlying speculations (or assumptions) by researchers, clinicians and even the general public about what fatter people are doing differently or feeling and acting differently that accounts for their increased fatness. These views are likely yet another source for deep-seated fat-biased beliefs and weight-stigmatizing judgments.
Should we stop doing this kind of research? Even as a public health ethics professional, this is not in my lane, so I can’t say. I think we should remain careful about uptake and reliance on nutrition research, lest it leave a bad taste in our mouths.
I enjoy yoga when I do it. I rarely regret it. But these days, like Cate, I’m finding it harder than usual to unroll my mat. I started out this strange time of staying at home with Yoga for Adriene. I think for June I’ll try it again.
“June 2020 Yoga Calendar – COURAGE. Yoga With Adriene Free monthly Yoga calendar! If this is your first time joining us for a community theme, welcome! Each month, we come together as a community around a theme that inspires questions and guides intention for a regular and sustainable at home yoga practice.”
“This year, I am fundraising for the Manulife Heart & Stroke Virtual Ride for Heart, in support of heart disease and stroke research. That research is more critical than ever right now, as emerging data confirms that people with heart disease and stroke are at a great risk for developing serious conditions if infected with COVID‑19. Heart & Stroke estimates that people with heart conditions are four times more likely to die from COVID‑19 than patients with no underlying conditions.
I’m pleased to learn that Manulife is TRIPLING donations during the month of May*. It’s a tremendous opportunity to TRIPLE your impact and make a difference when it’s needed most. Every donation counts and will be TRIPLED to help those who are especially vulnerable right now.”
You can sponsor me here. I had registered for the 75 km bike ride, Sunday, June 7th. My new goal is to ride 75 km that weekend, either indoors on my trainer or outdoors on the road, weather and life depending.
Just been flopping around, dragging from one prone position to another mostly? Ya, I know, it’s been a time.
What’s that? Yes, things are stiffening and there’s that weird thing where you don’t eat anything for 10 hours, unless you count coffee as a food.
Ya, well you don’t ALWAYS have to finish that project before you are allowed a sandwich. Yes, I remember those chicken mushroom crepes too. We could check to see if they are still in business. Yes, that would be nice.
Hey body, do you think maybe you’d consider moving a little more? No no, I don’t mean running. You hate running, especially when you are totally stressed out. I mean, maybe something that’s good for you, a strength/balance sort of thing.
Well, yes I know you’ve kind of had it with pre-recorded videos. No no, I’m not suggesting some kind of weird app. I was thinking maybe of a person, like a trainer?
Is it on Zoom? Well, yes, everything is on Zoom. Yes, I did read the last post we wrote, I was there, writing it. Yes video is not real life but body, that SI joint isn’t going to lubricate itself. I think you need some help.
Well, I heard that Cate’s trainer is online. She’s smart and funny and loves a puzzle. You know us, we are a bit of a puzzle. What do you say?
Hey body, you okay? You sound like you are about to cry (and I would know, seeing as I’m right here). Well of course I’ve been paying attention to what we’ve been doing to ourselves. It’s not been great, all this sitting still and slouching and general malaise. No, I was not intending to march us into age and immobility without so much as a glance back. I was just very very very bummed out. Yes, I know, it hurts and not just the stiff SI joint. I’m sorry, I really am, this has been hard on both of us.
Okay I will email her right now. Twice a week? Done, for a few months. Let’s see what’s happening and then we can make some more choices.
I’m glad I checked in too. I’m sorry I was ignoring you so much. This all just sucks so terribly.
Yes I can feel you are hungry. We should go eat something. Of course there will be cookies. I know, I love you too. Really I do.
Sam’s post on Wednesday on the not-funny joke about the two types of people in quarantine really struck me. I’ve been doing a lot of comfort eating, comfort reading, comfort tv viewing, and comfort napping.
Yes, I’m doing zoom yoga and walking outside. I’m out riding my bike (sometimes with a mask and sometimes without– stay tuned for more on Sunday’s post).
But like Sam and Cate and probably all of us, I’m not capable of functioning the ways I’d like all the time. That’s too much to expect of us no matter how rosy things are in the world. And they’re decidedly not rosy right now.
I wrote this piece around holiday time a while back. What it has in common with eating under pandemic conditions is: 1) the panic that comfort eating provokes in public discussions anytime; and 2) the absurd lengths to which the health/fitness industry will go to keep us from cookies or cake or pasta. To them I say put a sock in it. To you I say comfort eating is eating, which is one of many things we do. It’s really not going to kill us, which is even more meaningful now.
I don’t know the source of the above image but lots of friends have been sharing it on social media, some with critical commentary, some not.
I think it gets something very wrong. I suspect that most of us who are part of this blog community are to varying degrees both of these people. Fun comfort food, yay! Also, running streaks, daily yoga, and lots of time on Zwift.
Sometimes when I’m stressed because I’m sharing a small place with three other people all with our own busy work agendas or I’m feeling overwhelmed by the global pandemic more generally, I do Yoga With Adriene or take Cheddar for a long walk.
Sometimes like Cate I find I can’t do yoga. My mind is too busy. Yoga feels so slow and I’m easily distracted. I have even paused Yoga With Adriene to doomscroll. Really. Sometimes I’m stressed but my knee hurts too much to walk Cheddar. Or he’s already been out for three walks! He even hid one day because too many people had been walking him. He’s looking pretty svelte.
Last week I had a busy work afternoon that was super stressful. So much Zoom time. So many hard issues to discuss. I retreated to my bedroom with a bag of peanut butter M & Ms to watch BoJack Horseman, which I know is not an easy show but the thing is when I’m like this sometimes fluffy, easy, light shows aren’t enough to engage me. I’ve always liked BoJack, hard as it is. See BoJack Horseman’s running advice.
My point though, my main point, is that there aren’t obviously two types of people in quarantine. We’re all coping as best we can. Sometimes here that’s meant excessive/competitive baking. Sometimes it’s riding bikes indoors. And sometimes it’s laying in bed with BoJack Horseman and M and Ms.
There are lots of photos of Catherine McKenna–Mom. Swimmer. Climate advocate. Ottawa Centre MP/Députée. Minister of Infrastructure and Communities/Ministre de l’Infrastructure et des Collectivités–riding bikes. My fave are the Winter Bike to Work Day images. But this Bike to Work Day McKenna wore a dress (and a mask) and shared photos and the internet blew up with meanness like Twitter had never seen a woman riding a bike while wearing a dress.
Cute red bike and pink dress, right? That’s what I thought but I might be in the minority. There were lots of negative comments. I won’t share the meanest.
One Twitter user wrote, “So a short dress and a mask while riding a bike with a goofy basket wow. You look ridiculous.”
But feminist Twitter and women cyclists everywhere came to the rescue.
I added my “biking in a dress” photo.
Catherine McKenna responded with charm and good humour.
As mechanical engineers who consult on heating, ventilating, and air conditioning (HVAC) systems, we’ve been closely following the evolving body of knowledge about how the SARS-CoV-2 novel coronavirus (the virus which causes COVID-19) spreads through the air. We thought some folks might be interested to know some of what we’ve learned, and how that’s affecting our thoughts on returning to the gym.
Some of the science so far
So far, we know that droplets in the air we breathe out (and in) are infectious to varying degrees depending on the size of the droplets – and that those droplets have the potential to be propelled for varying distances.
Relatively large and heavy droplets fall on and contaminate surfaces. This is a whole other topic, but it seems to be relatively well-known and understood. Also it can be controlled with frequent cleaning, so it’s less important from an engineering point of view. At the moment, our big concern (and the focus of this post) is with the smaller, lighter droplets known as aerosols.
Scientists and engineers take particular note of so-called “superspreading” events (such as the ones that were mentioned in Saturday’s post because they point to clues about how an infection is transmitted in a variety of real-world situations.
In the example of the choir in Washington State one mildly symptomatic person infected 52 of their 60 fellow choristers over the course of one or two 2.5 hour practices. Besides sitting close together, it is thought that the act of singing, itself, might have contributed to transmission, as aerosol emission has been correlated with loudness of vocalization.
The dance fitness classes in Cheonan, South Korea gives valuable insight into what factors which affect the risks of exercising indoors. Sports facilities are generally considered to represent a higher risk of transmission due to the warm, moist indoor air coupled with the turbulent air flow generated by intense physical exercise, which can cause more dense transmission of droplets.
Six instructors who were infected at a workshop went on to teach classes for about a week. Not all of them were necessarily even symptomatic. Secondary cases were identified from fitness dance classes with as few as 5 people in a ~60 square meter (~645 square foot) studio. Notably, an instructor who taught 7-8 person Pilates and yoga classes at one of the same facilities did not infect any of her students. Together, these us some insight as to how transmission risk might be mitigated in the short term for group fitness classes : very small class size, limits on movement to maintain physical distance, less aerobically- and movement-intense activities.
In the long term, engineers and building owners will have to address the significant concern that was raised by another notable case of a restaurant in Guangzhou, China one patron infected eight others who were sitting more than 6 feet / 2m away. It appears that air flow from the HVAC system helped carry infectious aerosols from one table to another.
The role of HVAC in controlling transmission
The possibility that a normal HVAC system can carry it through the air over distances greater than the current physical distancing guidelines is a major concern. While we don’t yet know for sure how infectious COVID-19 is in aerosol form, the Epidemic Task Force of the American Society for Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE, the leading industries standards organization) have stated: “Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled.”
In hospitals, aerosols are controlled by continuously moving lots of air through infectious spaces to dilute them, adding lots of fresh air, careful airflow design, and HEPA filtration. All the air in a typical patient room is filtered about once every four minutes. While gym ventilation is actually comparable to that of hospitals – gyms need comparatively good ventilation to keep them from smelling bad – the circulating air may have little or no filtration. Even if a gym’s air handling equipment is modified with HEPA filters, to achieve that circulation the HVAC system draws air from one side of the space and blows it on the other side. Just like in the restaurant example above, air exhaled by someone will move through the breathing zone of those nearby.
When outdoor temperatures permit, it may be possible to make temporary changes such as opening existing windows and doors to encourage wind and buoyancy-driven natural ventilation in order to increase airflow and dilute contaminants in an existing fitness space. The openings need to be large to make a difference : a crossfit gym with a roll-up garage door and a back door propped open will be safer than a studio with a small open window. Openings on more than one side of the room gives better access to cross-breezes; openings high and low in the space will drive buoyancy flows, especially if the gym is warmer than the outside air. When natural ventilation is working well, the indoor air will smell like outside, and match the outdoor temperature and humidity levels, so the comfort of the occupants will vary accordingly.
Other approaches to improve airflow in gym spaces, such as redesigning the air distribution to direct fresh air directly onto each occupant, will be expensive and disruptive to install – and unfortunately, still not proven to be entirely effective against airborne infection. There are some HVAC solutions that will reduce the concentration of infectious aerosol droplets in the air in buildings, notably increasing outdoor air volumes; HEPA filtration; and UV lights that sterilize air above the heads of occupants. These solutions reduce, but do not eliminate, the risk of virus transmission.
What are the risks?
As gym patrons, we miss the motivation of exercising together with others, and access to equipment we don’t have at home. As we start to evaluate the risk of returning to indoor activity, there are a number of airborne infection risk factors which must consider in our decision making:
Indoor exposure: Whether an office, a store, or a gym, shared indoor environments have inherent transmission risk. Each additional person occupying the space with us increases the risk.
Extended exposure: Being the same place with specific other people for an extended period of time (15 minutes or more).
Stationary exposure: Being in the same position relative to other individuals for an extended period of time, especially if the air conditioning system is blowing past the person next so that you are breathing their air.
Increased respiratory droplet exposure: Intense aerobic activity, shouting and deliberate sudden exhalation reportedly increase the amount and spread of respiratory droplets. A low-intensity yoga class represents a lower risk than, for example, a Kiai (shout) filled karate class or high-intensity cardio class.
Mechanical system efficacy and state of maintenance: Many gyms and other fitness spaces are tenants in older or repurposed commercial spaces which are not always in the good repair. HVAC systems lose effectiveness as they get older, and may distribute air poorly. Some owners may even shut off HVAC systems due to safety concerns but these actions could actually increase risk if they reduce the outdoor air flow into the space.
Controlling the risks
For any given hazard, there are many different possible ways to address or mitigate the associated risks. Those who have taken a workplace health and safety course may recognize this hierarchy which is commonly used to rank the effectiveness of the various controls.
Preventing infection using an engineering control – like the fresh air system inside a gym – or administrative controls such as cleaning – is necessarily less effective than substituting a lower risk activity – such as exercising outside in places where physical distancing can be maintained.
Is outdoors actually safer?
Both published research to date and epidemiological consensus appears to indicate outdoor activities are extremely low risk: a recent, not yet peer-reviewed study of infections in Chinese cities outside Hubei province in January and February showed that less than 1 in 300 outbreaks (only 1 out of 7000 individual infection events) could be traced to contact that occurred outdoors. B.C.’s provincial health officer has been quoted going so far as to say “the risk [of catching the virus] would be infinitesimally small if somebody walks [or runs] by you.”
The evidence is strong that for the foreseeable future, substituting parks, backyards or even gym driveways will be a reasonably safe way to enjoy exercise with others, while indoor workouts will remain high risk until either the risk of exposure to infection can be eliminated, or effective engineering controls can be implemented. We want to support our fitness spaces, and we are hopeful that the summer weather will allow everyone to use the outdoors to bridge the gap until it’s safe to be together inside again.
Cara is an active promoter and designer of sustainable buildings, specializing in multi-unit residential and municipal facilities, enjoys dancing, Jeet Kune Do, acroyoga and circus arts, and bikes to get places.
Sarah specializes in existing residential and commercial high-rises, and the systems that make them habitable. She spends far too much time poking around the guts of buildings and not nearly enough time on road bikes, sailing dinghies, or skis.