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Understanding Sleep

May 3, 2022   Return

Sleep is a basic physiological drive; to feel a need for it is as natural as feeling hungry and thirsty. Just like how nutritious food nourishes the body, sufficient quality sleep is necessary to rest and rejuvenate both mind and body. It is not an exaggeration to say that our survival, proper daily functioning and overall well-being depend upon getting regular optimal sleep.

In fact, sleep deprivation is linked to a number of serious short and long-term health issues. Yet, when our hectic lives get the better of us, getting enough eye-shut often becomes an afterthought.

To truly understand the importance of sleep, we need to understand what actually goes on from the time we drift off to dreamland. We can then work around the factors that govern the natural sleep-wake drive to accommodate our lifestyle, and ensure we catch enough Zs.

The Architecture of sleep

There are 5 stages of sleep that passes through from the moment a sleeper drifts away from wakefulness. These stages – 1, 2, 3, 4, and Rapid Eye Movement (REM) sleep – are categorised based on changes in brain activity, as reflected in measurements of brain waves. They progress in cycles, from Stage 1 to REM and back again, repeating four to five times throughout the course of a typical night’s sleep with each cycle lasting an average of 90 to 110 minutes.

 Stage 1: Light sleep –

A few minutes into relaxation, the sleeper drifts from wakefulness. Body temperature begins to drop, muscles gradually relaxed, awareness of surroundings begins to fade and bran waves slowed into a pattern called theta waves. Stage 1 lasts for only about 5 minutes, and if disrupted, the sleeper is easily stirred back into wakefulness without being able to recall falling asleep at all.

Stage 2: Establish sleep –

Eyes stop moving, heart rate, breathing and brain waves became slower from the waking state. The sleeper can still be awakened by external or internal stimuli, such as loud noises nearby or being shaken.

Stage 3: Deep sleep –

At this stage, the sleeper’s blood pressure and pulse dropped to about 20-30% below waking rates and the brain becomes unresponsive to external stimuli. It now becomes very difficult to rouse the sleeper. If forcefully awakened, one will feel extremely tired and groggy.

Stage 4: Moving deeper into delta sleep –

This is the time for the body to renew and repair itself. The pituitary glands releases growth hormone to stimulate tissue growth and muscle repair, and the immune system also receives a boost.

REM sleep –

The sleeper enters the dreaming stage. The eyes dart back and forth under closed lids, breathing becomes rapid, while body temperature, heart rate, blood pressure and brain activity fluctuate to levels similar to wakeful state. Other than minor twitching, the body hardly moves, because all muscles besides those responsible for breathing and eye movement are temporarily paralyzed to prevent the sleeper from acting out their dreams. While deep sleep is necessary for physical health, REM sleep is needed for mental health. Dreaming serves a necessary function of clearing out mental clutter to better facilitate memory and learning.

Night Time is for sleeping    

Feeling sleepy and being wide awake is regulated by an internal biological clock, known as the circadian rhythm. This brain mechanism is influenced by various external factors, namely light and time cues, which explains why we feel alert during daytime and tiredness sets in when it gets dark.

Even so, sleep habits vary in different people. “There are 2 types of sleepers; morning larks and night owls. A morning lark tends to wake up early and go to bed early. A night owl on the other hand, tends to sleep late and wake up later in the morning,” explained Amy Ho, a registered polysomnographic sleep technologist, and Senior Sleep Technologist at the ASEAN Sleep Research and Complete Centre (an initiative of University Malaya Specialist Centre).

Whichever type of sleeper one may be, the typical adult still needs seven to eight hours of sleep each night for optimal health and proper functioning during the day. Moreover, it is unlikely for sleep needs to change as one gets older. “What will change is the sleep architecture, which may contribute to sleep problems among the elderly,” said Dr Izuan Ismail, Consultant Respiratory Physician and Senior Lecturer at the Faculty of Medicine, Universiti Teknologi MARA.

Shedding light on the common misconception, he explained why people sleep less with age, “Although the amount of sleep needed often remains constant, older people spend more time in the lighter stages of sleep than in deep sleep. They are also prone to advance phase sleep disorder, where they tend to fall asleep early around 8 to 9pm, and wake up at night.”

Nevertheless, the best way to ensure uninterrupted sleep is to practice good sleep hygiene. Your sleep hygiene refers to cultivating practices, rituals and behaviours before bedtime, and also the design of your sleep environment. Good sleep hygiene means cultivating habits that signals to the mind and body to relax and prepare for sleep, in a comfortable environment that is conducive to sleep.

The key to maintaining good sleep hygiene, Ho said, is consistency. “Set a regular sleep and wake time every day, including weekends and public holidays. This practice will anchor the biological clock at the desired time.”

She also offered a simple suggestion for good sleep hygiene; remove electronics such as a computer, TV or mobile phones from the bedroom, as these items emit lights that can delay sleep onset by a few hours. Furthermore, one may be stirred by the sound from their gadgets during REM sleep. “We have to associate bedroom with sleep and sex only, so no watching TV, working on the computer, eating or texting in bed. Your last meal should be three to four hours before bedtime. If you get hungry at night, a light snack is recommended,” said Ho.     

Never too busy to sleep

Often times, the common excuse for not getting enough sleep is being too busy and having too much to do. This may be a legitimate concern for those whose job requires frequent travelling and odd hour client meetings. In such cases, one could benefit from taking naps.

“A study at the National Aeronautics and Space Administration (NASA), US, on sleepy military pilots and astronauts found that a nap improved performance by 34% and alertness by 100%,”said Dr Izuan. However, napping has to be done correctly, with an understanding of the sleep architecture, for it to be beneficial.

According to Dr. Izuan, the key to effective snoozing is to avoid going into arriving at the deep sleep stage and waking up feeling more tired than before, “A nap should be about 20-30 minutes and not longer. Napping should not be too late in the day either, as it will affect night time sleep patterns. The best time is probably around lunch time, in the afternoon.”

Although it is ideal to maintain a sleep schedule during the same time frame each day, with as little variation to the routine as possible, it may not be feasible for certain individuals due to work-life demands, such as having to work night shift.  If you need to go against the natural sleep-wake rhythm, Ho recommended a few quick fixes:

  • Spend time outside in the afternoon or early evening. “This will help in staying up later and be more alert because the body is exposed to bright light.”
  • Exercise in the evening. “A walk or going to the gym will promote alertness.”
  • Taking caffeine. “Drinking coffee, energy drinks or chocolate, 20-30 minutes before work may help to boost alertness.”

While these short -term remedies may be helpful, they should be utilised sparingly as continuous sleep deprivation and living out of sync with the day is bound to take its toll. “Short-term consequences are feeling tired, lethargic, drowsy, irritable, unable to concentrate, decreased work productivity and increased risk of accidents. Long-term consequences include developing hypertension, diabetes, increase risk of heart attack and stroke, obesity, depression and impotence,” Ho cautioned.


ASEAN Sleep Research and Complete Center (ASRCC). Available at

Epstein, L., & Mardon, S. (2007). The Harvard Medical School guide to a good night’s sleep. New York: McGraw-Hill.

Sleep Disorder Society Malaysia (SDSM). Available at

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