Imagine choking for hours in your sleep each night, and not even knowing it.
That is what Mr Tay Tze Siong, 44, experienced for years, resulting in unrestful nights of sleep.
Mr Tay, who is an assistant manager in the entertainment industry, said: "I was always sleepy at work. Sometimes I even dozed off at meetings."
He added: "But I never thought much of it until my wife alerted me to the fact that, at times, I had stopped breathing in my sleep."
When he finally sought medical help, Mr Tay was diagnosed with a condition called obstructive sleep apnea. It occurs when the upper airway closes partially or fully, causing breathing to be disrupted during sleep.
More Singaporeans in their 20s to 40s are seeking treatment for the condition, said doctors. Compared to two years ago, doctors are seeing up to a 30 per cent increase in the number of sufferers here.
A growing awareness among the Internet-savvy is cited as the main reason for this, said Dr Ignatius Mark, an ear, nose and throat surgeon at Ascent Ear Nose Throat Specialist Group.
Dr Mark said: "It's as if someone is strangling you for seven hours straight at night. The body is under great stress."
Many of his patients are young working professionals, including lawyers and pilots.
He explains that these sufferers seek medical treatment when their work or lifestyles become affected by the condition.
Dr Kenny Pang, a sleep specialist at Pacific Sleep Centre, said of young professionals affected by the disorder: "They are tired, their memory is shorter, and they tend to be irritable.
"This affects their work, and relationships with colleagues, which could also result in lost promotions."
Doctors told my paper that sleep apnea cases here largely go undiagnosed, and that an estimated 15 per cent of Singaporeans suffer from the disorder.
Dr Lee Yeow Hian, a consultant in respiratory and critical-care medicine at Tan Tock Seng Hospital, said: "Many don't think much of their condition as they put it down to them being tired because they are working very hard."
The link to obesity
Dr Pang pointed out that an increasing obesity rate here has also led to the rise in incidence of sleep apnea.
This is because with more body fat in the throat and neck areas, obese people will have their airways narrowed, experts told my paper.
One common symptom of the condition is snoring. That is why a sufferer's spouse is typically the first to sense something amiss.
Ms Pamela Minkley, a medical education specialist from Philips Healthcare, said: "Snoring is an indication that the airway is partially closed and vibrating as one tries to pull air in to breathe."
Snoring might be common enough for many to ignore its potential to be a sign of something more serious, she added.
This is "one of the biggest risk factors" for the disorder, Ms Minkley said.
Beyond poor sleep quality, sleep apnea could even be hazardous to sufferers who take to the wheel, and to others on the road.
This is because sufferers have been known to fall asleep at the wheel, said Dr Lee.
"People diagnosed with the condition should temporarily stop driving for their own safety and that of others," he advised.
Dr Pang said that at least 20 to 30 per cent of his patients had "near misses or actual collisions".
Experts said that the obstruction of the airway for those with the disorder leads to great stress on the body and also increases the risk of high blood pressure, heart disease and stroke.
Treatment for the condition includes wearing a nasal mask to help keep the airway open or to blow air into the airway.
Dr Pang said: "It's best to seek treatment for the condition as you spend one third of your life asleep."
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