How Wearing A Mask Affects Endurance Training
Mayor Lightfoot just opened up the Lakefront Trail in Chicago. While many people have been using it for weeks before this, the official opening is an exciting milestone for endurance athletes. Instead of dodging cars and pedestrians, we can now run and bike freely and uninterrupted by stoplights.
But the Lakefront Trail isn’t completely open. Lightfoot has imposed several restrictions. The path is only open from 6am to 7pm daily. Trail users have to keep moving, and there is no congregating of any kind. Standard social distancing rules apply. Social Distancing Ambassadors will educate the public and manage traffic on the trail. Most importantly, trail users must have masks on at all times.
These rules come after people have been using the Lakefront Trail for weeks without following any of them. I have seen people fishing, lounging by the lake, using exercise equipment, and playing on the playgrounds. It’s difficult to imagine that city officials will suddenly be able to enforce rules they didn’t enforce before the trail opened.
The Mask Debate
There is a debate amongst endurance athletes about whether we should wear masks while training. The Chicago Area Runners Association (CARA), one of the largest running clubs in the United States, issued “Running Safety Guidelines” which recommend, “Run with a mask or face covering if you must run in places where you may encounter others, such as city sidewalks and trails.” There is also a great deal of social pressure to wear masks even when we are social distancing (check out my Masks of Chicagoland series for a look at Chicago’s mask wearing culture). Some people are very aggressive about it, too. Some athletes, especially women, report that they experience harassment when they run without a mask, though my social media polling said that they are in a minority.
Greg Hipp, the executive director of CARA acknowledges that masks are annoying, “We don’t like wearing a mask or face cover to run either, but it is the appropriate response to the times we currently live in.”
But do you need to wear a mask to stay safe? Social distancing rules suggest that it’s safest if everyone stays six feet away from each other. “There isn’t evidence that it’s dangerous to not wear a mask if you’re social distancing properly,” Said Dr. Kyle Barnes, Assistant Professor in the Department of Movement Science at Grand Valley State University. “But six feet isn’t a magic number.” He points to the famous study from Belgium, “Towards aerodynamically equivalent COVID-19 1.5 m social distancing for walking and running”, which shows that breath particles from runners, walkers, and bikers can hang in the air behind them for more than the traditional six feet, just shy of two meters.
The slipstream behind the runner allows breath droplets to hang in the air at a much longer distance “For walking at 4 km/h a distance of about 5 m leads to no droplets reaching the upper torso of the trailing runner. For running at 14.4 km/h this distance is about 10 m.” The study also concludes that running behind another runner is the most dangerous place to be. “This leads to the tentative advice to walkers and cyclists that if they wish to run behind and/or overtake other walkers and runners with regard for social distance, they can do so by moving outside the slipstream into staggered formation.” In fact, it seems like the safest place to be when running with someone else or passing someone is right next to them.
But you should notice what the study said about its own limitations. It does not take into account the effects of an external environment, like wind. “Further work will consider the effect of head wind, tail wind and cross-wind.” Neither does it consider the risk of infection when a runner or biker passes someone on the street. There’s a reason that even Dr. Fauci, the famous CDC spokesman, runs every day without his mask.
Even if you just want to be safe, a mask may not even be effective when you run. In a San Francisco Chronicle article, Dr. Allison Bond says that masks for runners are actually ineffective at stopping the spread of the Coronavirus. “Bond is a jogger and doesn’t wear a mask — but does keep 15 feet away from anybody else even if it means running in the street, during off-hours or off the beaten track. She said that when joggers sweat and their masks get wet, it’s not accomplishing anything anyway, because wet masks are ineffective.” Anyone who has covered their face in cold weather knows that a mask gets soaked immediately after starting to run.
National Federation of State High School Associations (NFHS)/Sports Medicine Advisory Committee (SMAC) released guidelines for high school athletics. “We recommend that cloth face coverings be worn by students during Phases 1 and 2 as outlined below. Exceptions are swimming, distance running or other high intensity aerobic activity.”
In summary, it is difficult to spread COVID-19 while outdoors, especially when you have only passing contact with someone, and a sweaty masks isn’t effective anyway.
How A Mask Affects Your Training
We all know that the racing season is uncertain during the coronavirus pandemic. Since March, every Spring race has been cancelled along with numerous Fall races. World majors, like The Boston Marathon, The Berlin Marathon, and others are among many races to fall before the pandemic. The upcoming racing season is a big question mark. Some, like the half ironman at Muncie, IN, are going forward while others are uncertain.
Runners still have to train to keep up their fitness even if they don’t know when they’ll race next. “While racing is up in the air,” said Elizabeth Waterstraat, pro triathlete and coach at Multisport Mastery (Full disclosure, my wife is also a coach there), “it’s always beneficial to focus on maintaining general fitness, building strength and improving a weakness. Other areas to consider would be working on nutrition, mindset, flexibility, relaxation — perhaps the little things that seem to get pushed to the side when we prepare specifically for races.”
“Most importantly, we want to avoid doing too much, too fast, too often. While [intense workouts] are often the workouts that feel good or give us the illusion that we are doing something productive, they can also be very corrosive to an athlete’s overall health and longevity.” Endurance athletes still need to do more than easy runs to maintain fitness, but Waterstraat said, “Doing just the right dose of anything is key right now.”
To understand how a mask can affect training, I interviewed several experts in the field of exercise physiology. While there has been no research on the different types of masks and their particular effects, these experts were willing to extrapolate from previous research to make hypothetical suggestions about the effect on training.
Increased Carbon Dioxide
Dr. Philip Clifford, exercise physiologist at UIC, says that one possible side-effect of wearing a mask is increased carbon dioxide. When the exhaled air gets trapped in the mask, it’s possible that the air inside the mask has increased CO2 levels. “If you breathe that in, you would increase the amount of carbon dioxide in your blood. Your O2 levels are probably adequate, but you have this response of your autonomic nervous system that controls breathing to make you want to breathe more than you are.”
In other words, this level of CO2 won’t actually hurt you, and it won’t affect the amount of work your muscles can do– that comes from the O2 level in your blood. It affects your perception of being out of breath. This perception is called “air hunger.” Dr. Horswill suggests that the biggest training risk from air hunger is that the runner would stop to lift up the mask. “The runner would stop to catch his breath long before it would cause a health problem.” In addition to feeling out of breath, raised CO2 levels can also cause headaches.
I have experienced symptoms like this while wearing my own homemade mask, but these symptoms can be explained by other causes, too. Dr. Barnes says that muscle tension might also cause my headaches. “A mask can cause the muscles around the face to contract. When you’re squinting the whole time or engaging the straps, it can give you headaches as well since you’re not in a relaxed state.”
“This is all speculative,” emphasized Dr. Clifford, “There is no actual research on this subject.” While the CO2 level in the blood is easy to test, testing the effect of masks on the level in the blood for different kinds of masks is complicated. “You have to test the effects of different kinds of masks, different materials, and different fits to be sure.”
Breathing Resistance
While the effects of trapped air inside the mask are at most a mild annoyance, the training effect of breathing resistance, called inspiratory resistance, is more likely to cause a problem during a workout.
Dr. Clifford’s research focuses on how the body regulates blood flow to the muscles. He said that increased inspiratory resistance will draw blood away from your legs and arms to your diaphragm. “Your respiratory muscles would want more blood and that would limit the amount of blood going to your working muscles. There’s a lot of research showing that if you’re working your legs at maximal levels, when you add your arms, you limit the amount of work you can do with your legs. There just isn’t enough blood.” This limits the amount of work your muscles can do when you run, which increases your effort level at a particular pace.
You probably already know about resistance breathers, sometimes inaccurately called altitude masks, designed to help strengthen your breathing muscles. Dr. Barnes’s research focuses on using resistance breathers to develop breathing strength. “The optimum is 50 percent inspiratory resistance with one set of 30 breathes, twice a day. It’s maximal breathing, so people get lightheaded. Most people can’t start off with all 30.” These resistance breathers work like strength training. “We call it dumbbells for your diaphragm,” he said. When your diaphragm is stronger, it takes less work to breathe while you run. “The relative work goes down…The fewer times you need to contract your diaphragm the less energy you need.”
This kind of breathing exercise isn’t just for elite athletes, either. Hospitals use resistance breathers to help strengthen breathing before doing surgery, and coaches have used them to help train gymnasts to get through their floor routines. Dr. Barnes said, “Resistance breathing is beneficial for everybody in a number of situations.”
But, he cautions, an athlete shouldn’t wear a resistance breather while running. Just like you wouldn’t do dumbbell curls during a tempo run, you shouldn’t try to do strength training for your diaphragm while running. “You can’t run at the paces you could without a mask. The question is, ‘What do you want to work on more?’ Typically in running, you’re going to elicit more benefits by running fast without a mask than you would by running slower with a mask.” If you want to get optimum training benefit for the amount of work your body is doing, take off the mask and run normally.
All this means that masks can strongly affect your training depending on how they are made. Trapped CO2 in the mask could increase the perception of being out of breath, which would force an athlete to slow down or stop in the middle of a run. A mask’s increased inspiratory resistance reduces the amount of work your muscles can do while running, which reduces the training effect at a particular effort level. So, you won’t get the most training benefits from a workout if you don a mask.
Response From CARA
Greg Hipp of CARA still recommends wearing a mask, though. Runners always modify their training based on conditions like weather, and he suggests that masks follow the same rule. “Aside from face covers, there are many external factors we as runners face on a routine basis that affect what pace we can run at a given intensity, such as heat, cold, humidity, wind, or even having to go to the bathroom. In these cases, we have always told runners to focus on intensity, more than pace. Training specificity requires targeting specific training adaptations. With some exceptions, the formula for training design is intensity x time = training adaptation. It is not pace x distance. Runners should not be overly concerned with having to slow down in training, so long as they are maintaining the correct intensity. Yes, pace and distance are the things we think of most, but only because they are so easily measured. In reality, they are just predictors of the factors that actually dictate how we reach a specific training adaptation.”
He added, “In the cases where runners need to target a specific race in training, maybe for the sake of building efficiency and comfort at race pace, a runner should take the appropriate precautions so they can run without a mask. That may be running at off-peak hours, or traveling to a location where it is easy to maintain social distance.” That sounds like good advice whether you wear a mask or not.
As for me, I can normally keep my distance when I run, whether on the sidewalks or on a trail. It’s usually simple to go around others or go down a different street. I am still hoping to get new PR’s in any possible Fall races, so I want every bit of training effect I can get. As states continue to open up, it gets more and more likely that the smaller Fall races will still happen. When I get there, I want to be as fast as I can be. Training without a mask is the best way to make sure that I am as fast as I can be. And, despite social pressure, it doesn’t seem like masks prevent the spread of COVID-19 when we combine outdoor conditions with social distancing. Others can do what they like, but I won’t wear a mask while I run.
