"It's funny if you think about it. We learn about a lot of things that we don't do, but we don't learn about something that we do all the time: breathe."
Andien, a popular Indonesian singer, shocked her fans when she posted a lengthy Instagram story about breathing - along with photos of herself, her husband and their two-year-old son with tape over their mouths.She revealed that her family had been practising something called Buteyko for the past three months. It involves finding ways of breathing through your nose - one of which is taping your mouth closed while you sleep.
Buteyko, Andien claimed, had helped her sleep better, had stopped her from getting dry throat, and had rid her of bad breath.
But does mouth-taping work and, more importantly, is it safe?
What is 'Buteyko'?
The Buteyko technique was first developed in the 1950s by the Soviet doctor of the same name, Konstantin Pavlovich Buteyko.
He believed that respiratory conditions, asthma in particular, could be linked to the way people breathed. He believed that if patients were taught to breathe correctly, through their noses, their lung problems would go away.Almost seven decades later and the alternative therapy remains popular, with Buteyko practitioners around the world now hailing the benefits of breathing exercises and taping the mouth shut to sleep.
Buteyko has been claimed to improve a host of ailments, from diabetes to chronic fatigue, ADHD and depression. But perhaps the condition it has become most closely associated with is sleep apnoea.
Sleep apnoea is when someone's airway is blocked or restricted while they sleep, which means they are unable to breathe as easily. As a result they get low quality sleep, which can lead to tiredness, depression, and other illnesses.
This is also why sufferers snore - that unpleasant sound is the air struggling to get in and out of someone's trachea.
Patrick McKeown, founder of the International Buteyko Clinic, told the BBC that "mouth-breathing is a big contributing factor to obstructive sleep apnoea (OSA)" because it can push the tongue back and obstruct the airway. Taping the mouth closed, he claims, can prevent this from happening.
'You don't just close your mouth'
But doctors disagree, and say that this is a simplistic understanding of the condition.
"I understand why it's preferential to breathe through your nose, but most people don't open their mouth unless they're having trouble breathing through their nose," Dr Kathleen Yaremchuk, a senior ENT surgeon and sleep specialist in Detroit, told the BBC.