As most of you know, I invited all of you to participate in a little homeschool science experiment concerning masks. There are a few negative things said about the health consequences of mask wearing, most of which we could never test out at home. But pulse oximeters make it possible to test one thing easily: whether or not mask wearing negatively affects a person’s oxygenation. My hypothesis, which I stated at the outset, was that it would negatively affect oxygenation.
I know what you really want to know: was she right or wrong? For now I will tell you that I appear to be both. The answers — and my new thoughts on masks — are much more nuanced than I expected.

We discovered quite a few things about oxygenation and masks along the way and honestly I wish I could redo this experiment. I would write the procedures up a different way. I’ll explain my thoughts at the end.
First, I will share my data. (We had quite a few people sign up to do the experiment, but only seven people turned in their data. This means my family of six is about half the data set. This, of course, makes the data even less statistically significant than it already was. Not that I was pretending we were actual scientists.)
The Data
Here’s the part where I tell you I was wrong. Most of the people in the test were able to maintain oxygenation within safe ranges. How do I define safe? Well, I did a bunch of research beforehand and discovered that 95% oxygen saturation is the usual cutoff between “okay” and “mild hypoxia.” It’s also generally accepted that brain dysfunction begins at 89% and brain damage begins at 85%. Only one person dropped into the brain damage range — my 15-year-old daughter (I explain about this — keep reading).
A few things you will want to know:
- The initial baseline was established by sitting restfully for 10 minutes before taking the measurements.
- The exercise baseline was established by 10 minutes of brisk walking and then taking the measurements immediately.
- The masked exercise was 10 minutes of brisk walking with measurements taken immediately.
Homemade Masks

As you can see, only one person dropped into the mild hypoxia range, and that was during exercise. My state, at least, lists exercise as an exemption.
N95 Masks

Missing data is due to two persons not able to complete the experiment due to hypoxia. More details about that below. I wish the graph didn’t go up to 101%. I don’t think there is any such thing when it comes to oxygenation! But I couldn’t figure out how to fix it, so there you are.
Surgical Masks

I am the yellow column. I must tell you I am quite proud of those O2 levels. Yes, yes, I breath strangely in a mask and yawn a lot. But I feel a little triumphant. I was severely anemic in my late 30s and it has taken many years and a whole lot of work and research to bring myself to the point where I am now. When I first put on the oximeter and noticed that when I am without a mask, I am consistently at 99-100% no matter what I do, I was so thankful to God for allowing me to reach this place because I was quite despairing at one point.
About Those Who Had to Discontinue the Test
I did this experiment on myself first. In a mask, I feel like I struggle to breathe (as evidenced by my continual yawning and other odd behaviors that I can hardly control). But when I did my initial test (which I completed), I was fully oxygenated at the 15, 30, 45, and 60 minute marks. Yes, it was lower than my base (I am usually at 99%, no matter what I’m doing, according to my oximeter), but still within the safe range.
I decided to try again, this time wearing the oximeter continuously. I plummeted again and again into the low 90s (anything below 95% isn’t really safe, brain dysfunction starts at 90, I believe). So all the gasping and yawning was actually my body’s cry for help. Yes, at the recorded minutes (15, 30, 45, and 60) I was technically fine, but those numbers weren’t the whole story.
My Daughter
When I did the experiment with my 15-year-old daughter, I required her to wear the oximeter the entire time. She dropped to 93% after 10 minutes. With me coaching her on deep breathing, she brought it back up and at minute 15, I recorded her saturation at 98% (you see why I’m kicking myself on how I designed the study).
At minute 27, she dropped to 91%. Again, I coached her on deep breathing and again oxygenation was restored and at minute 30 I recorded her saturation for the test as 98%.
At minute 35, she plunged to 89. For a number of minutes I worked with her to try to get it back up, but when I couldn’t get her above 92%, I discontinued the test.
During this time, she was sitting in a chair and reading. She wasn’t walking, lifting, or doing anything as strenuous as what we’d do at, say, Costco (where she would be required to wear a mask).
We went ahead and tried the exercise portion of the experiment. She dropped enough to set off the alarms multiple times, once all the way to 81% saturation, but nothing so long that I felt she needed to stop (she was only at this brain damage level for a few seconds). I had to stay with her and coach her on her breathing the entire time, but she made it through with a final saturation of 97%, which is not dangerous.
My Son
When I did the experiment with my 11-year-old son, I was shocked. This child cannot safely wear a mask for any length of time, and I’m really not sure why. The first time I put a mask on him, he dropped within 10 seconds to a saturation of 88%. I seriously thought it was a fluke. I tried again, and this time I had to ask: Are you holding your breath? Doing anything weird with your fingers? I asked a variety of questions, but really he was doing what he had been doing during the unmasked resting period when all his measurements were fine.
That afternoon, I found him reading and tried again. I put a mask over his head and the oximeter on on his finger. It wasn’t quite as dramatic as before, but 15 seconds later his oxygen saturation was at 92%.
I tried the exercise portion. My theory was that we all breathe differently when we are exercising than we do at rest, so perhaps he’d have more success there. After 15 seconds, his oxygenation was again at 92%.
Because it wasn’t safe, I discontinued the exercise portion of the test as well.
My Thoughts on the Experiment and its Results
Needless to say, I have a number of them.
How I Would Redesign the Study
The biggest change I would make is require continuous oximeter wearing and require notes to be made anytime a participant set off an alarm (which could be for pulse rate or oxygen saturation). A couple people made notes telling me they were surprised by their numbers because they feel like they are really struggling. My thought after my own continuous wearing is: maybe they are. How can we know unless they wear it continuously. There is nothing magical about taking a measurement at 15 minutes. Maybe we need to know what happened at 13 as well!
Continuous wearing would also give us a better idea about a person’s baseline. Since I had my children doing continuous wearing, I realized one was setting off alarms while exercising without a mask. Apparently, she holds her breath while exercising without realizing it. I told her to work on remembering to breathe and her numbers were fine while wearing a mask, but let’s think about what might have happened: if she had only taken her oximeter reading at the end of minute 10 and then hadn’t been coached to remember to breathe (which I shouldn’t have done until the test was over but I didn’t think about at the time — I had already gone into mothering mode without thinking), she might have done poorly at the masked exercise and I would have blamed the mask, but her lack of breathing would likely have been the real culprit.
Family Guidelines Set in Place
My primary reason to do this was to get real information about my own family, and now I have. I learned that my struggles with breathing through a mask are real, not psychological or imagined. (I did wonder if it was a type of claustrophobia.)
The new state mandate has a medical exception written in, so I can bring all my children with me (not that we go many places these days) without worrying they are in breach of an order. My two who didn’t make it through the experiment are simply not allowed to wear masks. We told them that if an adult asks or demands they wear a mask, they simply say they are not allowed to wear one and refer those adults to their parents.
Have Some Compassion
I’ve heard some adults say masks are fine, people who don’t want to wear them are being whiners, and they just need to toughen up and take one for the team. Those same adults seem okay about demanding children go back to school wearing masks for six to eight hours per day.
I’ve also seen some who refuse to wear masks act like the people wearing masks who say they are fine are lying. They couldn’t possibly be fine; they are delusional.
Here’s what I observed regarding oxygenation: some people are really, truly fine. My husband is a good example. He can wear a mask indefinitely and never drop in oxygenation, not even while exercising (at least exercising for ten minutes in the experiment — perhaps a longer duration would reveal something different).
But I also observed this: some people are truly not fine! My poor son’s reaction was so extreme that even I thought it couldn’t be real. I don’t know why he responds this way — maybe he’s allergic to what the mask is made of, I don’t know — but his response is real. My daughter’s is, too, and I take it seriously that once she even ended up in brain damage territory (which is different from dysfunction).
So my thought is that it’s possible that the people who aren’t comfortable wearing masks aren’t comfortable for real, measurable reasons. How about they go without masks and everyone just accepts that? I don’t think we should be asking some to brain damage themselves, and I truly wonder who is going to protect the children. I doubt my neighborhood school is planning to examine the oxygenation of the students, but I think they should. Not because all children will have a problem, but because some will, and we should protect them.
What I Recommend
I think that if you are concerned about mask wearing for yourself or your family members, you should either buy a pulse oximeter (this is the one I own), or go to a facility that will allow you the use of theirs for a while. Then, go ahead and do this same experiment. Find out your baseline. Wear an oximeter and watch your measurements for a whole hour. Take a brisk walk and find out whether that changes anything and, if so, by how much.
Basically I’m recommending informed consent. If you’re going to submit to wearing a masks, I think you should evaluate the risk. There are a number of them, but the one you can measure and observe is this one, and that’s a good place to start.
26 Comments
I definitely feel claustrophobic in a mask, as well as when seeing others in a mask, including images of masked people. I imagine them to be heavy and thick and suffocating. It causes me to feel suffocated. So when I read your reference to “a type of claustrophobia,” I said, “YES!” It is very real. The feeling is so awful that I will only go where they acknowledge exemptions. But it is getting so bad for me personally that I find I am avoiding going out at all because I am burdened by the possibility of being hounded or accosted. It’s only happened once at a gun store, and the library would not permit me to enter, even though I showed them that the state had exemptions. I live in Cali where they are getting militant about the masks. You have presented a great experiment here, and I read it to my 24-year old son who pointed out that unfortunately no one is interested in facts anymore. So yeah, they will put keep those young, healthy children in masks all day regardless of the unhealthy environment.
Thanks for doing a write up! I was very curious to see the results after you mentioned the experiment on IG.
I would like to add one idea to the discussion. To wear a mask or not to wear a mask is not really the heart of issue. The true issue is whether the government can require mandatory mask wearing. From what I understand it is a violation of the right to privacy.
If individuals want to wear masks, that is reasonable. Like one commenter mentioned, many Asian cultures wear masks as a courtesy. I don’t believe there is a law that requires them to do so.
This is SUCH a good point. Our government is increasingly encroaching on basic freedoms, from the forced purchasing of health insurance under Obama, to the force vaccination of school children here in California, to the forced mask wearing in so many states. Last fall, our state legislature passed a law that said that our health officials can do WHATEVER THEY DEEM NECESSARY once a health state of emergency has been declared. So technically, if they want to lock you up in your house without food, that’s legal. It’s frightening to me how many people think “it’s just a mask.” It’s *not* just a mask when it’s being written into law; at that point, it’s also precedent.
Where I live, I honestly think the mask mandates are causing MORE people to not wear masks than might have otherwise because it’s become a symbol of rebellion against tyranny.
I know I’m late to the party on this post, but I thought I’d offer two plausible mechanisms for why some people might have trouble wearing masks.
First off, there’s the actual physical reaction that happens during an anxiety attack– narrowing of airways. Anxiety attacks are not primarily a psychological phenomenon– I’ve met plenty of people who didn’t *feel* anxious but finally realized that their symptoms of chest pain or airway constriction were symptoms of a negative anxiety feedback loop. I’d imagine menopausal/perimenpausal women are particularly susceptible, as there is the added sensitivity to heat whereby the anxiety might trigger heat flashes.
Another mechanism that I think may be at work is the pressure certain masks can put on nasal passages when worn— if you have any kind of nasal swelling, or anatomically narrow nasal passageways, pressure on the bridge of your nose can reduce airflow. And like another comment said, breathing through the mouth isn’t the solution.
Those both make sense to me!
I know I’ve been told before that people with generally restricted airflow (like asthmatics) will have a much more difficult time. While my youngest’s baseline wasn’t low, he IS the one child I have suspected might have exercise/allergy induced asthma. He’s had a handful of incidents over the years, nothing major, but I’ve wondered if what is going on with him might be something along those lines because I honestly think it is happening too fast for there to be a buildup of CO2 in the mask.
My second son has similar issues– anatomically narrow nasopharynx/face structure (his dad has the same thing, as does his nana and his great-grandfather did, too), and a propensity for allergy-induced asthma (his allergies are primarily chemical so they are easy to avoid). He turns into a mouth-breather at the slightest sign of inflammation. 🙂 He hasn’t been too bothered by the masks we’ve used for the limited times he’s been out, though, for which I’m grateful.
We have been playing around with orthotropics and the Buteyko exercises to help maximize his palate growth potential, and I do think it has helped reduced his tendency to snore when he’s sick!
You know, I keep meaning to look into Buteyko and haven’t. Do you have a link for me on that?
All of my children did Orthotain and with half of them it worked AMAZINGLY (no braces required even though they started out with mouths so small their baby teeth were crooked) and with the other half it helped quite a bit.
Interesting experiment! We only have one pulse ox for my daughter, but it would be fun to try with all the kids.
I wonder what the psychological effect was on the wearers and whether people who expected to have trouble breathing had more issues (as they perhaps changed their breathing pattern unconsciously).
Our 8-year old has cancer, and over the years we have seen children as young as 2-years-old running around in both pediatric surgical as well as N99 masks in the hospital play room and the Ronald McDonald House. The kids never seem to have any breathing issues, nor do their doctors seem concerned that medically complex children are wearing masks for hours on end.
However, I’m currently pregnant and for the first time I do seem to have trouble breathing in an N95 mask (surgical mask still seems fine) when I’m walking or climbing stairs, although I don’t always have a choice in wearing it because of having a vulnerable loved one. I realize it’s a hugely political issue now, but I do wonder if our pre-conceived notions can influence our experience to some extent.
That’s interesting — especially since in our state the masks are not recommended for toddlers. I have wondered about pre-conceived notions and also psychological responses. I wish I knew more about how to sort those kinds of things out without expensive machinery!
Thanks for sharing your experiment and findings! I was actually very curious about your severe anemia in your late 30’s. That’s me currently, and I’m curious if you ever found any interesting cures. The iron pills and upping spinach is not doing the trick. Anyhow, glad you’re past that now!
YES! I did all the iron things and it didn’t work. I finally found a doctor who said I had B-vitamin related anemia. Two kinds, actually (lucky me): one that was due to folate deficiency and another that was the beginning of pernicious anemia (which usually doesn’t hit until age 40 — likely my other doctor would have caught it eventually), which is B12 deficiency. I did need to take iron as I was building my blood supply back up, but doing that alone still left me severely deficient.
Fun to see how you did this for your family. I would just add here, although you have probably looked into it, that there are numerous labs that spend a great deal of time and energy doing experiments like this…all sorts of masks, materials, exercises, length of time and on and on and on. Might be interesting to look at results of these studies…
Also, did you try just using homemade masks (Im sorry if I missed this!)? The point of mask wearing for ordinary folks as I understand it, is not to prevent the virus from coming through the mask (of course it can) but to minimize the droplets that come out of our mouths when we breathe/talk/sneeze etc. Even homemade masks can decrease droplets from a range of 8 feet to 4 inches or less.
I have seven children all under 12 who wear homemade masks if we go out…they slip them under their chins but put them on if we come near other people. We have only taken them for hikes and bike rides in wide open places, (Only one adult in the house is doing shopping) so sometimes they do wear them while breathing hard, but most of the time we are alone and outdoors so they take them off…but I still feel like it is just a thoughtful gesture to others if things get crowded. (We live in a huge city…I wouldn’t feel the need in a rural area). But if a child really can’t wear a mask…is it too much to ask that they just get to stay home as much as possible if the trip is to an enclosed place like Costco?
I’m really horrified about how political mask wearing has become when there are huge studies proving that droplets can be so well contained when we wear them. My friends mother from a Japan has worn them while out and about her whole life. When I asked her about it she just quietly said “it isn’t a matter of paranoia in my country, we just believe in being thoughtful and respectful of others”.
My Dad is from a tiny town in Idaho. I understand with 4 total cases in his whole county since this all started is a good reason for him not to go to all the extra precautions that I take in a tiny city of millions…but still on Memorial Day, he was exposed to someone with Covid at a cemetery where he was helping the American Legion. He and numerous other people were quarantined for 14 days because there was no mask wearing. My Dad was not one of the men who ended up getting the disease after exposure…but it was a lot of stress on him to be alone at 80 years old for those 14 days. But wearing a mask creates so much anger in his state from others he is too embarrassed to wear one.
I promise I do and will continue to think the best of others if they choose not to wear a mask! I know it is complicated and personal. Just thinking out loud.
Yes, there are many, many mask studies. I’ve shared some of them around here in the past. I read many studies per week, but only share my favorites here so as not to overwhelm.
I’m sorry your dad was exposed! It *is* stressful to be alone. The worst part of lockdown is how lonely and forgotten our elderly feel. I think especially of my grandmother with Alzheimer’s who doesn’t understand why people can’t come to see her. I’m glad your father didn’t get symptoms. Probably he has some great T cells to thank for that. ♥
As far as homemade masks go, we collected data for three kinds of masks: homemade, surgical, and N95. The N95s are what I keep on hand for dust storms because they prevent inhalation of Valley Fever spores, a disease which is endemic here. Valley Fever is much larger than Covid, so the masks can filter all of it (as long as it fits properly).
https://aricjournal.biomedcentral.com/articles/10.1186/s13756-015-0086-z
A study was done a few years ago on pregnant health care workers who wore the N95 masks.
“Conclusions: Breathing through N95 mask materials have been shown to impede gaseous exchange and impose an additional workload on the metabolic system of pregnant healthcare workers, and this needs to be taken into consideration in guidelines for respirator use. The benefits of using N95 mask to prevent serious emerging infectious diseases should be weighed against potential respiratory consequences associated with extended N95 respirator usage.”
Thank you for sharing this, Joy! This was a study I haven’t seen before.
Thank you for doing this and for sharing the results! I love your thoughts on your results and that you are now more informed as to the specific health needs of your family. Very inspiring! I agree that we each need to make informed decisions regarding mask wearing based on evidence of risks and benefits.
I’m glad you payed your results. I’ve been wondering how it turned out. Good thought, Mystie. A control group would be needed. If you try having your family wear the pulse ox continuously, I would like to hear how it goes. 😊
I’m curious, Brandy…are you and/or your children who had trouble with the masks mouth breathers? I have read that mouth breathing while wearing a mask noticeably decreases oxygenation compared to wearing one while breathing through your nose. I know mouth breathing is much less efficient in general, and I suppose wearing a mask makes this noticeable for some people. Which is not to say that there aren’t other things that could cause difficulty getting enough oxygen while wearing a mask.
I don’t *think* so, but I could be wrong. Now you have my curious! I will have to do some investigating.
Hi Brandy,
I read your email update on using masks and just wanted to leave a brief comment.
First, your experiment intrigued me; I”ll have to try it with our family.
Second, I am interested to understand how you did this with your oximeter. I am mom to 4 children with a rare lung disease. We have several pulse oximeters in our home – everywhere from the $2000. bedside one that is commonly used for continuous monitoring in the hospital, to a finger one similar to what you linked to in your article. Even with the most expensive of these pulse oximeters I have not found one that would read accurately when used in vigorous movement. Even the one you mentioned in your article specifically states on Amazon that “Also, you must remain stationary while the pulse oximeter measure your pulse and SpO2.”. I have also found, that particularly with the fingertip ones, finger size is an important piece of the puzzle with a smaller finger being much harder to find an accurate reading on. Another thought that would be interesting to me is to track respiratory rate and heart rate as well mask vs massless and during exercise.
I do agree we need to be thoughtful about mandating something that changes the way our body interacts with its environment, especially with something so constant and necessary as breathing. My children already work harder to breathe than most so it will be interesting to see how it affects to wear a mask. At the same time, it seems like wide-spread mask wearing really will protect many, like my children, from catching this virus.
For continuous wearing during the brisk walking, I used a treadmill (not required by the procedure, but convenient since I own one) and hand the measurement hand stabilized on the handle. This oximeter seems pretty accurate. We were able to verify the heart rate accuracy using both the treadmill sensor as well as our blood pressure monitor. I was impressed by the accuracy considering the price (my nephew has bronchiectasis and my sister warned me about the things you are saying about accuracy, movement, and such).
I would be very curious about your results if you do it! I know a number of asthmatics who say the mask wearing is causing them to triple inhaler use and struggle with oxygenation and a friend of mine explained it this way: asthmatics usually start off at 95% as a baseline, so anything can easily make them hypoxic. I didn’t know that before! With that said, my sister feels like the hygiene of people who come in contact with my nephew is so poor that he needs to wear a mask even though he would be allowed a medical exemption.
I totally agree that it would be interesting to track heart rate. I didn’t include that data because I feel far less informed about heart rate — I don’t know how to interpret the data! I thought about having a friend who is a doctor look at it. But my real point is: interestingly enough, my son that becomes instantly hypoxic also has an immediate rise in heart rate of at least 10bpm. He mystifies me. He is super sensitive to a number of other things, but now I want to but a monitor on him when he is exposed and see what is going on there. So strange.
I can answer the last paragraph! Since your son becomes hypoxic, his body recognizes he doesn’t have enough oxygen and increases the heart rate to circulate oxygen faster. Animals (and presumably humans, but I’m a veterinarian) have faster heart rates when they are not getting enough oxygen due to heart disease (and other things).
Thanks for sharing your results. I have been wishing someone would measure actual oxygen, rather than the videos of measuring CO2 in the mask which says nothing about what a person is actually inhaling (since they don’t only inhale the air in the mask). I also have been wishing it was someone I knew, because it feels like there are so many ulterior motives and potential deceptions flying around the Internet. And after many years of following you, I think you honestly try to be subjective. 🙂
I am pretty firmly on the mask-wearing side of things, because I think the research supports it, but I wish it would be effective without a mandate. Judging by how people are responding to strong recommendations by our (Republican) governor, who is trying really hard not to mandate it, I doubt it will. 🙁 I definitely realize that some people can’t wear masks for medical reasons (like this – which might not even have been realized without the pulse ox). I think it is such a shame it has become so political, and it’s not simply that those of us who are not adversely affected by masks wear them to protect those who are. But I think mandating masks outdoors in most places is silly and not supported by research, so masks should mainly only be needed for sedentary indoor activity. (In case you’re interested, this is my favorite summary of the research, citing many other studies: https://www.preprints.org/manuscript/202004.0203/v2)
I wonder what your thoughts are about comparing masks to seat belts and helmets (especially when masks are a temporary measure). Since the point of masks is mostly to protect others, and seat belts/helmets only protect ourselves; it seems like we should, in the personal liberty realm, object much more to that! I think it is far better to try to slow spread of the disease with masks and distancing than to have mandated lock downs (which I fear is the alternative). When I’m working I wear one when I am close to people (especially because I work in different cities and could carry the virus between them). Thankfully, my family is low risk, but I have colleagues (relief veterinarians) who feel like they are endangering themselves or family members because no one in their workplace wears masks – but otherwise they could not work. That’s an awful choice to have to make.
I wonder if it’d also be advisable to wear the oximeter continuously normally for awhile as well to see what fluctuations (if any) might be normal.
Interesting experiment, and a good idea to see how things actually affect your family.
For sure! In fact, I now think that is an interesting thing to do, even if masks are no longer an issue. I found it helpful to discover I had a child holding her breath while exercising! (No wonder she finds it so stressful.) It would be interesting to find out if she does it in other situations.
I know that I alarm normally as when I am in hospital on a finger monitor I have low blood flow to my extremities, especially when inactive. My surgeon asked me to clench the rest of my fingers/hand regularly to get more blood flow. A baseline O2 test without the mask would be interesting to see. Maybe this is what is happening to your son?
Interesting. I’ll try it! Thanks!