He has lost a job and caused a traffic accident, all because of a disorder in which he stops breathing repeatedly in his sleep.

Business designer Benjamin Pham, 29, was diagnosed with obstructive sleep apnoea about two years ago. A year earlier, he had started feeling sleepy during the day, and found himself dozing off in the office and at meetings.

Once in 2014, Mr Pham even fell asleep behind the wheel. "One moment I was driving, and the next moment I had collided into a car in front of me," he recalled .

It was only when some friends took a video of him sleeping as a prank, that he realised something might be wrong. "In the video, I could see myself gasping for air in my sleep," said Mr Pham.

He took a friend's advice and went for a sleep test, which monitors body functions during sleep, such as breathing patterns, brain activity and blood oxygen levels.

"The test showed that I woke up 17 to 25 times an hour. I was not really sleeping and not getting enough rest," said Mr Pham.

In October 2014, he underwent surgery to widen his narrow nasal and throat passages, which his doctor said were the cause of his condition.

"It didn't really work. It got a bit better, but it was not the miracle cure I was hoping for," he said.

The persistent problem led to a poor performance review at work, which eventually cost him his job.

"My boss didn't understand my disorder and chose not to renew my contract."

His constant fatigue also left him with little energy for exercise. At one point, this caused the 1.71m- tall bachelor, who was already overweight, to balloon to 80kg.

Mr Pham later bought a Continuous Positive Airway Pressure machine, which pumps air into his air passage during sleep via a mask.

He used it diligently for four to five months, but found it inconvenient. "It's troublesome when I need to use the bathroom or when I stay over at a friend's place." Now, he uses it only once or twice a week, or when he has an important meeting the next day.

Mr Pham, who has a family history of sleep apnoea, is worried about the associated health problems, such as heart failure and diabetes.

"I try my best to diet, exercise and not be so stressed."