IT WAS almost midnight when I started my research for this story.

Along the way, I got distracted by a friend's MSN message. We chatted for a while before I returned to my work.

By the time I decided to go to bed, I was simply too wired up to sleep, so I fiddled with my mobile phone and played my favourite game. I finally willed myself into a fitful sleep after 3am.

Needless to say, I was a wreck when my daughter woke me up at 9am the next morning.

A good number of people may find the above scenario familiar.

Inadequate sleep may sometimes be due to sleep disorders. However, in many cases, people often do not have enough sleep because they voluntarily choose to forgo sleep for other activities, said sleep experts.

While there are no formal statistics, Dr Lim Li Ling, president of the Singapore Sleep Society, reckoned that many adult Singaporeans do not get the daily six to eight hours of sleep that is needed for optimal well-being.

"Lack of sleep is a common and largely under-recognised cause of daytime sleepiness and other health problems in countries such as Singapore, where the lifestyle is hectic and round-the-clock activities (such as online shopping and games) are available," said Dr Lim, who is also the medical director and consultant neurologist at the Singapore Neurology and Sleep Centre at Gleneagles Medical Centre.

According to her, most people who have problems falling asleep generally have bad habits that are not conducive to healthy sleep.

"For example, it is common to see people work till late at night, and thus do not have enough of a wind-down period. This can make falling asleep difficult because the mind is not relaxed enough."

Dr Lim added that she noticed that most people do not get enough physical exercise and use stimulants such as caffeine to stay alert, habits which can affect one's quality of sleep. Long daytime naps, stress and eating late can also interfere with sleep.

To encourage Singaporeans to sleep more, the Singapore Sleep Society is introducing the Sleep An Hour More Movement when its Singapore Sleep Awareness Week (SSAW) launches this Friday.

The society is urging Singaporeans to "switch off your mobile phone, computer or TV, tuck in early, sleep in later or take a nap in the day", in order to sleep an extra hour each day (bosses, are you reading this?) during the 10-day campaign to feel the physical differences.

For obvious reasons, chronic sleep deprivation can cause excessive daytime sleepiness, fatigue and weariness, lack of concentration, irritability, a lousy mood, as well as affect cognitive function such as problem solving, learning and memory, said Dr Jenny Tang, medical director of SBCC Asthma Lung Sleep and Allergy Centre at Gleneagles Medical Centre. It can also affect one's immunity.

Lesser known negative effects include risking a bigger waistline.

Explained Dr Tang: "When people are sleep deprived, there is a chance that there will be a change in the balance of their appetite hormones, which results in a bigger appetite and desire to eat more."

She added that heart palpitation could also occur when people overuse stimulant substances such as caffeinated beverages to counter sleepiness.

"Through raising awareness of the many serious health issues which can arise from long term lack of good quality sleep, we hope to encourage more people to make sleep a priority for the sake of their emotional and physical wellbeing," said Dr Lim.