I have always been skeptical about the safety of wearing a mask while exercising, not only because the death of two Chinese teenage boys, who was wearing a face mask running laps in gym class at the time[1], but also out of my personal experience – difficulty in breathing walking upstairs. If it happens when simply walking upstairs, it will just get worse while running.
A video on YouTube showed that the demonstrator’s internal oxygen level didn’t decrease when wearing a mask. And of course, there is a person who can still finish almost a full marathon wearing a mask[2]. Yet how to explain the death of those two Chinese kids and the feeling of difficulty in breathing?
It all comes down to our body regulation.
From iStock
Oxygen Consumption at Rest and During Exercise
First let’s do some calculation. At rest, an average person consumes about 0.3 L of O2/min[3]. During normal quiet breathing, about 500 ml of air moves into and out of the lungs with each breath[4]. The average resting respiratory rate for adults is 12 – 18 breaths per minute[5]. Therefore, we breath in 6 L to 9 L of air/min. At sea level, dry air contains 20% of O2. This means that the amount of oxygen we breathe in a minute is 1.2 L to 1.8 L. This is 4 to 6 times more than what our body needs to consume. As a result, it is easy to see that under resting conditions, wearing a mask doesn’t deprive our body of oxygen supply.
During exercise, our breathing pattern changes from involuntary breathing to voluntary breathing, or hyperpnea. Oxygen consumption goes up as exercise intensity increases. During vigorous exercise specifically, ventilation can increase 10- to 20-fold in order to support our skeletal muscles. Although not yet fully understood, many control mechanisms are involved in the regulation of breathing such as neural factors[6].
Endurance training improves a person’s maximal aerobic capacity (VO2max), meaning more oxygen delivered to, and used by the working muscles, which is also called conditioning. A trained marathon runner can better utilize the oxygen he/she breathes in.
As for the tragedy of the two Chinese boys, firstly, their pulmonary system may have not had fully developed yet. Second, it was a long winter break due to the pandemic, and their aerobic capacity was not as good as before. Both factors may have contributed to the inability of their body to better utilize oxygen.
The type of mask being worn during exercise also plays a part. The more tightly woven the mask or more layers, the greater resistance it has. As a result, we need to inhale and exhale more often (increase ventilation rate) even stop the exercise if our body can’t catch up.
What Mask Should I Wear?
Although we know it doesn’t feel good wearing a mask while exercising, when we work out in a place where social distancing is difficult to maintain, or it doesn’t get to the point where it is unbearable to wear one, some of us may still want to add some extra barrier. Plus, wearing a mask is mandatory in some places. So, what kind of masks are the most comfortable to wear during exercise?
I did a few tests. I found four types of face masks and face coverings at home. A surgical mask, a silk face mask, a neck gaiter and a polyester mask.
First, I did a light test to see how transparent each mask is. Light test shows that the silk face mask is the best at blocking the light.
I also did a water test to see how the fabric of each mask interacts with a waterdrop. As we can see, the surgical mask completely blocks the waterdrop. For the neck gaiter, the waterdrop stays for a while before penetrating the fabric. Waterdrops “disappear” almost the same time they touch the silk and polyester face masks.
Since I got the neck gaiter and fabric face masks from the manufacturers, I need to wash them before putting them on. To wash them, I used normal temperature water with some detergent, and hand washed each for 20 seconds. Then I used a towel to absorb excessive water before hanging to dry.
Next I put on each mask and went out for a jog. I also did a separate test with a lanyard connected to the mask, and a removable filter inserted, respectively.
Then I rated these masks according to the light test, water test, fit, breathability, moisture-wicking ability, convenience, and if it causes skin irritation, in a scale from 1 to 5.
Here’s my result:
Comparing the results, I concluded that the best face cover for me to wear while jogging is the 2-layered neck gaiter.
Why the 2-Layered Neck Gaiter is the Best for Jogging?
What makes the 2-layered neck gaiter the winner of this test? Let’s take a look at the fabric and configuration of these face masks and face covers.
Surgical Mask
The surgical mask is composed of 3 layers. Both the inner and outer layer are non-woven fabric, which is water resistant, or hydrophobic, as we can see from the water test. The non-woven layers block the water in the air from coming in from outside and going out from inside. The moisture-wicking feature is important for activewear, because sweat is not able to vaporize and therefore cannot dissipate heat. Furthermore, one time use surgical masks should be reserved for people who are in dire need.
Polyester Face Mask
Although the polyester face mask has 2 layers and an extra layer for a filter, the fabric is so loosely woven that it’s fairly porous, as we can tell from the light test. This implies that this face cover is not very good at filtrating particles.
Silk Face Mask
The silk face mask runs the best in the light test, which I presume is because of its relatively small porosity. This implies that the silk face mask has better filtration efficiency. Similar to cotton, silk is hydrophilic, meaning that the fabric absorbs and traps moisture, rather than wicking moisture. The silk face mask does well in retaining droplets from the wearer, yet it also means that it’s not good at wicking moisture. That and the softness of natural silk makes it difficult to breathe while jogging. However, adding a removable filter helps stiffens the fabric and ease the problem. Since the silk face mask performs so well in other aspects, it will be my light activity pick.
Neck Gaiter
The neck gaiter is made of 1-layered knitted polyester. Polyester is hydrophobic, as we can see from the water test, the waterdrop stayed on the surface for a while before penetrating the fabric. The neck gaiter folded into 2 layers has a similar effect at blocking the light as the surgical mask, implying good filtration efficiency. As synthetic fabric, polyester is moisture-wicking and one of the best types of material for activewear.
Even though the 1-layered neck gaiter had the highest score, its lowest filtration efficiency puts it out of consideration. Similarly, the lowest moisture-wicking ability of the silk face mask puts it out of competition, despite having the same average score as the 2-layered neck gaiter.
Back to the question - should I wear a mask while exercising? I will try not to. By saying that, I mean I will try to exercise in a safe environment. If I want to jog, I will try and pick a time and place when and where it’s not crowded, and I will bring a face cover with just in case. If I want to lift weights, I will choose to do it at home (Things You Need to Know About Working Out at Home). If I don’t feel well, I will rest at home, instead of risking my life and others.
Image by Gerd Altmann from Pixabay
Bottomline, keep social distancing and wash hands often. If a social distance cannot be maintained, wearing a face mask is an extra barrier that you can add to protect others and yourself. Choose a face mask or face cover that balances the protection and breathability. Because if a mask does not breathe well, you will pull it down, rest it around your neck, under your nose, on your chin etc. This is not what we want.
P.S. Don’t wear face masks with exhalation valves or vents, which allow virus particles to escape. For more information regarding use of masks, please visit WHO or CDC website.
[1] JESSICA SCHLADEBECK, “Two Chinese boys reportedly die within week of each other while wearing face masks in gym class”, NEW YORK DAILY NEWS, MAY 07, 2020.
[2] BEN SNIDER-MCGRATH, “Doctor wears mask on 35K run to silence anti-mask protesters”, Canadian Running, AUGUST 2, 2020.
[3] W. Larry Kenney, Jack H. Wilmore, David L. Costill, Physiology of Sports and Exercise. Six Edition.
[4] Elaine N. Marieb, Katja Hoehn, Human Anatomy & Physiology. Eleven Edition.
[5] Barrett, Kim E.; Barman, Susan M.; Boitano, Scott; Brooks, Heddwen (2012-04-05). Ganong's Review of Medical Physiology (24 ed.). p. 619. ISBN 978-0071780032.
[6] See 4