A breathing technique said to help people with COVID-19 symptoms is getting praise from “Harry Potter” author J.K. Rowling and CNN broadcaster Chris Cuomo.

A British doctor — identified by The Times as Dr. Sarfaraz Munshi from Queen’s Hospital in London — demonstrated the exercise in a YouTube video that's received almost 2 million views since Friday.

In it, he urged patients to begin practicing the technique right at the start of their coronavirus infection or even before any symptoms began.

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Rowling was a fan, tweeting Monday that it helped her relieve recent respiratory issues:

Please watch this doc from Queens Hospital explain how to relieve respiratory symptoms. For last 2 weeks I've had all symptoms of C19 (tho haven't been tested) & did this on doc husband's advice. I'm fully recovered & technique helped a lot.https://t.co/xo8AansUvc via @YouTube — J.K. Rowling (@jk_rowling) April 6, 2020

On Tuesday, Cuomo tweeted he's been performing the technique fives times a day:

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YES. 5x day. And I do stuff on tummy. And I walk a little and take big gasps. Still fighting fever waves. Last night was depressing. Decent day then fever all night. https://t.co/pdMSfIbssm — Christopher C. Cuomo (@ChrisCuomo) April 7, 2020

The technique:

Here are Munshi's instructions:

Take a deep breath in.

At the end of it, hold your breath for five seconds, then release.

Do this five times — five breaths total.

Next, take a sixth deep breath in, then at the end of it cough strongly — covering your mouth when you do so.

The six breaths plus cough at the end represent once cycle. Repeat this cycle twice.

Munshi then instructed patients to lie on their stomach on a bed, taking slightly deeper breaths than normal for the next 10 minutes. “The majority of your lung is on your back, not on your front,” Munshi said in the video. “So by lying on your back, you’re closing off more of the smaller airways and this is not good during the period of infection.”

He credited the exercise to Sue Elliott, director of nursing at the Partnership of East London Cooperatives. She did not respond to a TODAY request for comment, but other experts endorsed the exercise.

Why the technique works:

“There are a lot of good points there,” Dr. Albert Rizzo, chief medical officer for the American Lung Association, told TODAY. “It's not specific to COVID-19... any condition that leads to a lot of mucus can be benefited from this.”

The idea is to get the lower part of a person’s lungs to expand so that any mucus that’s collecting there can be dislodged and then coughed out. The initial deep breathing helps all the airways to open up, then the cough at the end of the sixth breath helps loosen the mucus that’s been affected by those deep breaths, Rizzo said.

Patients with the severe type of COVID-19 are often described as “drowning in their secretions,” so anything that can get the mucus moving so it can be coughed out would be beneficial, he added.

Lying down afterwards is part of what doctors call postural drainage, or putting a person’s lungs in a position so that gravity can pull any loose secretions out of the organs.

Rizzo would recommend the technique for people who already have coronavirus symptoms such as a cough and shortness of breath. A person who is infected probably needs to repeat it several times a day.

Rizzo advised trying it while seated since such breathing can lead to dizziness for some — as it did for Munshi, the doctor in the video.

Still, doing the technique wouldn’t prevent someone from getting COVID-19, Rizzo said.

“To think that doing these breathing exercises puts you in better shape to handle COVID-19 is probably not the right message,” he noted.

“(But) deep breathing can also be helpful for mind and body and meditation and relaxation. Just the act of concentrating on your breathing may release some stress, make people feel good.”