Researchers from SingHealth Polyclinics (SHP), a member of the SingHealth group, embarked on a search for answers to find the reasons for Singaporeans not sleeping enough and the effects it places on their health. They discovered some interesting information.

Dr Tan Ngiap Chuan, Director, Research, SHP, who led the study, said, “There are many studies out there, but none were done to compare sleep patterns of residents in two local housing estates with different population profiles. Our study helps us identify common factors that lead to the loss of sleep among Singaporeans.”

A standard questionnaire was used by researchers on 350 people, aged 21 to 80, who visited the Sengkang and Bukit Merah polyclinics, and the findings were published in an international medical journal.

They found that 44 per cent of participants – young people and those over 40 – slept less than seven hours a night on weekdays. A large proportion of this group were students and full-time workers.

This group, however, appeared to catch up on their sleep on weekends. “They seemed to make up for it on Saturdays and Sundays. We found that just over a quarter were sleep-deprived on weekends,” said Dr Tan.

By contrast, those without fixed work commitments, such as homemakers, retirees and the unemployed, more often had consistently adequate sleep on weekdays and weekends.

Those who got enough sleep tended to have regular sleep times, fall asleep relatively easily, exercise regularly and not smoke.

How lack of sleep affects health

The body heals and repairs itself during sleep. Prolonged lack of sleep can therefore impact the body in many ways.

Physical impact

  • Daytime fatigue
  • Poor stamina
  • Higher risk for obesity and chronic diseases such as hypertension, diabetes and metabolic syndrome
  • Shortened life expectancy

Mental impact

  • Less effective cognitive perception, affecting performance
  • Impaired judgement and reaction time, affecting safety
  • Memory and concentration difficulties

Emotional impact

  • May cause mood disorders, depression and anxiety

Lifestyle affects sleep

The study also found that modifiable factors, mostly lifestyle practices, were responsible for affecting people’s ability to get enough sleep. Among these were:

  • Sleeping in the same room as children
  • Studying or leisure reading late into the night 
  • Using computers or mobile devices in the bedroom or in bed
  • Drinking caffeinated beverages before bedtime
  • Smoking

Those who used computers or mobile devices prevalently – surfing the Internet or playing computer games in the bedroom – tended to sleep less than seven hours on weekdays. Interestingly, using one’s handphone in bed did not shorten sleep times, although this observation requires further research.

Dr Tan said using computers and electronic gadgets in the bedroom is a modifiable behaviour. Changing it can help improve sleep patterns.

“We plan to come up with a checklist for patients. So if a patient consults us for sleep-related problems, we can quickly go through the common modifiable factors, ask the relevant questions, and offer a quick solution.”

But this does not mean the sleep-deprived have to bid goodbye to their devices at the bedroom door. “They can still use their devices, but they should put them away and let their minds rest at least one hour before bedtime. It’s like a cooling-off period, so to speak.”

Effects of caffeine and smoking

Other lifestyle factors found to affect sleep were drinking caffeine and smoking. People who had caffeinated drinks two hours before bedtime were less likely to get enough sleep.

Smoking has consistently been shown to affect sleep because nicotine is a well-known stimulant. The study also found that smokers, or previous smokers, tended to have less sleep compared with non-smokers.

“Smoking alone significantly increases the risk of vascular diseases. The risk is further heightened by a lack of sleep because insufficient sleep is also associated with cardio metabolic syndrome, a phenomenon where certain risk factors come together and cause a higher likelihood of diseases such as atherosclerosis and diabetes,” he said.

“Consulting a physician for sleeprelated complaints gives the doctor a chance to persuade the patient to quit smoking as a means to ameliorate sleep insufficiency.”

Dr Tan also noted the long-term effects of insufficient sleep, particularly reaction time on the roads. “If more people are able to sleep adequately, it may reduce the number of accidents, and everybody will be safer,” he said.

Ref: O17

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