Tom Lawton is an ICU doctor in Bradford Royal Infirmary.
He told the Yorkshire Evening Post he had seen 'the worst of what coronavirus can do' - even to people in their 20s and 30s.
Tom said he was upset 'to see misinformation' about oxygen levels being affected by wearing a mask.
To prove his point, he raised over £1000 for the Trussell Trust by completing a 22 mile run from his home to work and back - wearing a mask for the duration.
Tom said: "I've done this because, working on ICU and in the hospital, I've seen some of the worst of what this virus can do - even to people in their 20s and 30s.
"I don't think there's a single magic bullet that will fix this but a whole series of things we can do which play a small part each.
"One of those, and one of the easiest, is probably wearing masks.
"So it upsets me to see misinformation about oxygen levels etc that might scare people away from them."
Tom said he believed he was putting 'at least 10 people's worth of oxygen through the mask' during the run.
He also carried an oxygen SATS meter which he claimed showed 98% oxygen levels throughout.
Tom added: "I'd never actually run in a mask before doing it for real.
"I was confident in medical and physiology training."
At time of writing, Tom had raised £1,180 for the charity.
He said: "The choice of the Trussell Trust for fundraising was because they run the main food banks I'm aware of in Bradford, and many nationally.
"They were already needed too much prior to 2020, and the pandemic has made things worse for so many people - I've seen reports on how many children don't have enough to eat right now so I feel it's something really important to try to help."
To donate to Tom's fundraiser on GoFundMe, click here.Tom provided an update following his run on the page.
He added: "The mask didn't come off at all (not even for food or drink during the runs) - and oxygen levels were stubbornly 98% every time I checked.
"Please feel free to cite this when anyone suggests they're bad for you, and stay safe - and COVID-free."
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