Wanchai used to be a noisy sleeper. His loud snoring not only annoyed his children but also made them worry that he might have an underlying health problem.
A patient undergoing an overnight sleep study.
"My daughter told me that she could hear my breath catch once in a while during the night when she passed my bedroom. That sometimes scared her as she thought that I had stopped breathing," said the 69-year-old retired army officer who now works for a company.
He told Life that a few years ago he noticed that he felt more exhausted than before. A feeling of fatigue often prevented him from exercising after work.
"I felt drowsy by the late afternoon. I thought I'd slept well the previous night but still wanted to sleep," he said, adding that he usually fell asleep around 9pm and got up around 5.30am.
With his children's encouragement, Wanchai decided to seek advice from a specialist who asked him to take an overnight sleep test (polysomnogram). The results showed that he had interrupted breathing during sleep, a condition known as obstructive sleep apnoea (OSA).
"Since OSA occurs when people are asleep, they are not aware of it," said Dr Visasiri Tantrakul, a sleep medicine specialist at Ramathibodi Hospital.
Snoring is a sign of the condition. According to the specialist, patients with OSA can have pauses in breathing many times a night, or all night long. And each pause can last from seconds to minutes.
"Most of my patients come to see me because people who sleep in the same room or share the same bed with them want them to see a professional. They cannot stand their loud snores," said Dr Visasiri.
''Obstructive sleep apnoea is as common as diabetes. It's something that people are not able to control,'' said Prof Douglas McEvoy, senior director of the Adelaide Institute for Sleep Health at the Repatriation General Hospital, who visited Thailand last month.
''The main symptom of the condition is an obstructed passage of the throat when they are sleeping. This interferes with their breathing and places a lot of stress on the cardiovascular system, on the heart and on the brain. So, it could be a significant cause of excessive cardiovascular disease.''
An estimated 5-10% of people around the world have sleep apnoea. There is a growing number of people with the condition due to rising levels of obesity _ a major risk factor for the condition.
In Thailand, between 5-10% of the population have sleep apnoea.
In Australia, according to Dr McEvoy, about 26% of men in the country's Northern Territory suffer from the condition.
''The number is much higher than previously thought. The reason for the high figure in Australia is because more people are gaining weight,'' said Dr McEvoy.
A 2009 study by Dr Visasiri on the prevalence of sleep apnoea among the 3,000 employees of Egat, the country's electricity provider, showed that 11% of them have the condition. Significantly, this group of people, especially those aged 40-55, also had high levels of obesity, high blood pressure and other metabolic syndromes.
Other potential causes of snoring include physical features such as a small throat and soft palate tissue that can narrow the airway.
''Extra fat around the tongue and throat in obese and overweight people can cause blockages in the airway,'' said Dr Visasiri.
Dr McEvoy said people regard snoring as an annoyance, but it is a potentially serious problem in terms of cardiovascular health. Because people with sleep apnoea stop breathing for long stretches, the obstruction causes very low oxygen supplies to the body. When the obstructed airway opens there is a large increase in blood pressure causing the heart to work harder, which in turn places considerable stress on the cardiovascular system.
''We know that people with sleep apnoea don't sleep well at night. People who are chronically tired are not productive. Students cannot learn effectively if they have sleep apnoea. Adults cannot turn up for work. If they do turn up, their brain is not present,'' said Dr McEvoy.
He added that patients with sleep apnoea face two to four times increased risk of motor vehicle accidents compared to those without the condition. The most common invasive treatment for sleep apnoea is a continuous positive airway pressure (CPAP) device _ a pressurised mask which the patient wears while sleeping. The mask is attached to a small pump that forces air through the patient's airway to keep it open.
Using a CPAP device has changed Wanchai's life.
''Since I started using it, I no longer wake up with a bad headache. I'm glad that I'm able to go back to work as well as enjoy playing golf that helps me manage my weight,'' he said. In the past, Dr McEvoy said, apnoea patients would treat themselves by sleeping in a sitting position, or sleeping on the kitchen table.
''They had to sit up because if they lay down their sleep apnoea got worse. They could not sleep. Lying on their side also helps,'' he said.
''CPAP is a tool that helps people with snoring,'' said Dr Visasiri. ''It keeps the airway open, thereby preventing pauses in breathing and helping them sleep better. They may have to rely on the device all their life.''
Other treatments for snoring include oral appliances and surgery to correct structural problems in the mouth and throat.
Dr McEvoy cited a Spanish study that found that sleep apnoea increases the chance of having a heart attack or stroke among patients who refused any treatment for 12 years. Patients who receive CPAP treatment reduce the risk of a heart attack or stroke.
There is increasing evidence that sleep apnoea, if not treated, can be an increased risk for cardiovascular diseases.
''It should be noted that not everyone who snores is experiencing difficulty breathing,'' Dr Visasiri said. ''Ask your sleeping partner if you snore in bed and be sure to consult your doctor if your partner says your snoring is loud.''
Electronics firm Philips is screening one million people worldwide for obstructive sleep apnoea over the next five years. To be part of the screened group, go to www.areyousnoring.com to do an online risk assessment test.