Ever since the great mask debate of 2020 came out I have wondered what the truth is. Do masks actually reduce blood oxygen levels? And how much do they reduce blood oxygen levels during exercise? After all, I have heard that just by wearing a mask you can reduce your blood oxygen levels by up to 20%, which would be extremely dangerous.

I do actually have my own political views, but I do not believe that they should influence health information, unfortunately, for some reason, they have. For that reason I do not feel that I can believe anything that I hear on the news or radio, so I like to actually test things out for myself.

And that is exactly what I did.

I bought a pulse oximeter, which reads both your pulse and your blood oxygen levels. You probably have used one at the doctors office.  They put it on your pointer finger and get some information off of it, that information is your pulse and your blood oxygen level.

Then I set up three days for doing cardio. Each day was going to be as similar as possible, eliminating unwanted variables. Here are the constants for all three days:

1. Same start time – I started my cardio workout between 5-5:30 AM each day.  Our body chemistry changes as the day goes on, so by starting my test first thing in the morning I eliminated those factors.
2. No food – I started each session before any food intake.
3. 150 mg of caffeine – I take a small amount of caffeine before cardio to help metabolize fat and for a little energy boost.
4. Same visual stimulation – certain shows get you pumped, others mellow you out, I watched one episode of the same type of show each day.
5. Same piece of cardio equipment – I used the elliptical at the Green Physique each day at the same resistance and elevation.

The only variable was the mask. Day one I wore no mask, this is the control day.
Day two I wore a cloth mask.
Day three I wore an N95 mask.

Before I began, I believed that my O2 levels wearing a mask was going to be a little lower than with no mask and much lower while wearing the N95 mask.

My actual results were much different.
There was no difference between wearing no mask, a cloth mask, and an N95 mask.

Day 1 results (Control – No Mask):
Blood Oxygen before starting: 98-99
Blood Oxygen 15 minutes in: 97
Blood Oxygen 30 minutes in: 95
Blood Oxygen 45 minutes in: 96

Day 2 results (Cloth Mask):
Blood Oxygen before starting: 99
Blood Oxygen 15 minutes in: 97
Blood Oxygen 30 minutes in: 96
Blood Oxygen 45 minutes in: 96

Day 3 results (N95 Mask):
Blood Oxygen before starting: 99
Blood Oxygen 15 minutes in: 97
Blood Oxygen 30 minutes in: 96
Blood Oxygen 45 minutes in: 96

The end result and my take: you can wear a mask and workout and not worry at all about your oxygen levels.  The masks are kind of annoying to wear when you are exercising, but they are not going to effect you the way that some people say.

I recorded all of my readings, and my end evaluation if you would like to watch the whole thing, it is in the video below.