Published on 28 October 2021

    Why is sleep important?

    Sleep is such an ordinary occurrence that it’s easy to overlook the bounty of effects it has on our bodies. We spend up to one-third of our lives in this natural paralysis without truly recognising the essential role it plays. 

    While it doesn’t get the same celebrity attention as diet or exercise, sleep is one of the most important contributors to our wellbeing. “The primary function of sleep is for mental, physical and especially cardiovascular health. When you sleep at night, your body rests and your heart rate goes down. Your body is not meant to keep working tirelessly without getting the physical, hormonal and mental restoration it needs at night,” said Dr Adeline Tan, Senior Consultant, Respiratory Medicine, Ng Teng Fong General Hospital

    What happens when we don’t get enough sleep? 

    Have you ever had a bad night of sleep? Chances are, you didn’t feel too good the next day, as the lack of quality sleep adversely affects your physical, mental and emotional states. 

    In the short-term, not only does it impair your ability to learn, memorise and make logical decisions, but it can also cause your blood pressure to spike. 

    “Your mood will probably be affected. You might become grouchier and irritable. Your cognition might diminish as well. You would probably slow down considerably, not think so clearly and make errors in your judgement,” explained Dr Tan.

    The long-term effects are even more grievous, as sleep quality is greatly linked to the vitality of our cardiovascular and mental health. 

    “If you are not getting enough good, restful sleep, it will exacerbate mental disorders such as anxiety and depression. In fact, insomnia is probably a risk factor for anxiety, depression and a whole host of other mental illnesses. Additionally, if you don’t get the recommended seven to eight hours where your heart goes into a proper rest, eventually your cardiovascular health will suffer. Therefore, short sleep or poor quality sleep is very highly associated with cardiovascular issues such as hypertension, heart attacks and even heart failure,” said Dr Tan. 

    How much sleep is enough? 

    So what is the magic number when it comes to sufficient sleep? 

    “I recommend that my patients sleep between seven to nine hours a night, which is what studies have shown is the optimal amount of sleep that correlates with good health. Anything below six hours, which is quite often what Singaporeans get, is probably not that ideal,” said Dr Tan.

    There is also an optimal time frame for sleep, based on something known as our circadian rhythm, or our intrinsic body clock. “Ideally you’ll want to sleep from 10-11pm to 6-7am. There is a circadian rhythm of which your body maximally gets the rest and recovery it needs, which is based on the time frame your body is exposed to sunlight. Your melatonin levels start to peak around 10pm to 11pm, so if you can capture that window, you’ll probably get better quality sleep.”

    Characteristicsinclude: Vivid dreamsIncrease in brain activity Rapid Eye Movement Sleep Active Sleep Final sleep Lightasleep Deep sleep Non-Rapid Eye Movement SleepQuiet Sleep main stages of sleep There are 2 stages sleep cycle Divides into 4 Sleep time per night 75 % 25 % Falling asleep Each Cycle Of Sleep Last The Optimal Number Of Hours And Sleep Cycles I Should Get 5-6full sleep cycles = REM Circadian Rhythmis an internal, biological clock that regulates our sleep-wake cycle EVERY24HOURS NREM Don’t use electronic devices before sleep. Unwind before bed with relaxing activities. Get 30 minutes of vigorous exercise in the day. Avoid smoking or drinking alcohol. Get enough sunlight in the day. It’s possible to still be tired aftera good night’s rest because you didn’t spend enough time in the deep sleep phase. The majority of your dreams occur in REM sleep. vs INFANTS/CHILDREN ADULTS 20 % 50 % DEEP SLEEP OF REM CYCLE 7.5-9 hours 90-120 mins However, it is important to note that good sleep stamina does shift with age. "Unfortunately as you grow older, your sleep will not be as smooth and uninterrupted as when you were younger; your sleep may not feel as refreshing as before. A lot of people are stressed that their sleep quality deteriorates as they age. However, you have to learn to adapt, because the more you get stressed about sleep, the more your body physiologically reacts to the stress, and it becomes a vicious cycle. It exacerbates what was probably not such a serious problem at the start. This is probably the start of many cases of psychophysiological insomnia,” said Dr Tan. Fortunately, for a lot of us, good sleep can be secured with the help of consistent sleep habits and routines. “People often buy expensive supplements, but one great way to improve your health is to have good sleep hygiene habits, including regular exercise, avoidance of smoking and alcohol and electronic devices before bedtime,” concluded Dr Tan. In Conclusion

    In consultation with Dr Adeline Tan, Senior Consultant, Respiratory Medicine, Ng Teng Fong General Hospital.

    Download the full infographics here.

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