Ten guidelines for a healthy life: Korean Medical Association statement (2017).
December 15, 2017 148 p (in English)

doi: https://doi.org/10.26604/979-11-5590-078-9-93510-5

Having a Regular Sleep Schedule

Having a Regular Sleep Schedule

Remember: Sound and regular sleep leads to a healthy life


◆ Background

Healthy sleep is an indispensable part of physical and mental health. Maintaining sleep hygiene is essential for sound sleep.

◆ Purpose

To present the key guidelines for sleep hygiene.

◆ Contents

1. Maintain a regular wake-up time and if necessary, take a nap for less than 30 minutes

Waking up at a regular time allows a regular sleep cycle to be maintained, which ensures sound sleep. Additionally, taking a nap for over 30 minutes is not recommended, as doing so can affect nighttime sleep.

2. Get enough sleep

In the short term, insufficient sleep can affect one’s judgment, mood, and ability to acquire and retain information, as well as increasing the risk of serious accidents and bodily harm resulting from drowsiness. Sleep duration can vary across individuals; however, getting enough sleep, in accordance with one’s age, is good for concentration and mental health.

3. Thumbs up for regular daytime exercise! Thumbs down for caffeine, alcohol, and tobacco!

Daytime exercise improves the overall duration and quality of sleep by stabilizing circadian rhythms. Intake of caffeine, alcohol, and nicotine reduces the quality of sleep.

◆ Expected impact

By offering key guidelines for sleep hygiene, sleep health is expected to be ameliorated, as one’s physical and mental health can be promoted by getting good quality sleep.

Keywords: Sleep, Sleep hygiene, Sleep quality, Health, Regular-wake-up time, Exercise

Best practices to follow

1. Maintain a regular wake-up time and if necessary, take a nap for less than 30 minutes

2. Get enough sleep

3. Thumbs up for regular daytime exercise! Thumbs down for caffeine, alcohol, and tobacco!

Fact Sheet ➊

Maintain a regular wake-up time and if necessary, take a nap for less than 30 minutes

Our body has a ‘biological clock’ that controls our sleeping and waking functions 24 hours a day. Keeping one’s eyes closed or lying down too much during the daytime disrupts this biological clock, resulting in sleepless nights when sleep is most needed [1-3]. Additionally, remaining in bed when one does not feel drowsy might cause the habituation (or conditioning) of insomnia, which means that our body gets accustomed to the state of arousal in bed.

1.1 Wake up at a regular time

Making it a rule to wake up at a regular time helps to maintain the sleep cycle and to ensure sound sleep. No matter what time you fell asleep the previous night, no matter how refreshed you feel, you need to wake up at a regular time every morning. Setting a daily alarm for certain times in the morning can help.


1.2 Go to bed only when you feel sleepy; if not sleepy, get out of bed

Going to bed only when you feel sleepy helps you sleep, because that way you fall asleep faster and wake up less often [1].

If you cannot fall asleep even long after getting into bed, getting out of bed and waiting until you become sleepy is much more helpful. You might not have slept well the previous night, which could easily trick you into thinking that you need to go to bed earlier because you are tired. However, it is important to wait until your body sends you a signal that you are sleepy. You fall asleep instantly when you go to bed drowsy, which reinforces the association between bed and sleep and helps your future sleep. Forcing yourself into bed when you do not feel sleepy will only exacerbate the problem; thoughts of things that happened during the day, worries, and various stray thoughts will keep you from physical and mental relaxation, awakening you all the more.

1.3 Do not take long naps

Taking a nap for over 30 minutes is not recommended, as it can affect nighttime sleep.

Naps disrupt the sleep-wake cycle, thereby disrupting sleep at night. Lying down too often during the day disturbs our ‘biological clock,’ which makes it hard for our body to feel the need to sleep at night. In fact, not only actual sleeping, but mere lying down with our eyes closed can confuse our biological clock, which easily mistakes this for proper sleeping. Therefore, one should avoid napping, and naps should be for less than 30 minutes when unavoidable [4,5].

Homeostasis of sleep means that the need for sleep increases in proportion to the time one spends awake during the day; a nap reduces homeostatic sleep drive, so it disturbs nighttime sleep.


Fact Sheet ➋

Get enough sleep

The U.S. National Sleep Foundation has suggested the following age-specific daily sleep duration necessary for physical and mental health:

Newborn (0-3 months) ––– 14-17 hours

Infant (4-11 months) ––– 12-15 hours

Toddler (1-2 years) ––– 11-14 hours

Preschool (3-5 years) ––– 10-13 hours

School age (6-13 years) ––– 9-11 hours

Teens (14-17 years) ––– 8-10 hours

Young adult (18-25 years) ––– 7-9 hours

Adult (26-64 years) ––– 7-9 hours

Older adult (≥65 years) ––– 7-8 hours


Sleep performs various functions pivotal to human health, such as improving learning ability and memory, maintaining homeostasis and body temperature, and maintaining proper immune function. Insufficient sleep in the short term can impair judgment, control over one’s emotions, and adversely affect the cognitive information processing. Moreover, drowsiness can increase the risk of serious accidents and injury. In the long term, chronic sleep deprivation can lead to health issues such as obesity, diabetes, cardiovascular disease, and even premature death. In particular, insufficient sleep among teenagers is associated with depression and suicide, according to a previous study in Korea [6].

Fact Sheet ➌

Thumbs up for regular daytime exercise! Thumbs down for caffeine, alcohol, and tobacco!

3.1 Regular daytime exercise helps to increase deep sleep and total sleep duration

In studies assessing sleep, daytime exercise and sleep hygiene have been reported to have beneficial effects, such as increasing the quality, duration, and efficiency of sleep, as well as alleviating daytime dysfunction [7].

However, care should be taken regarding exercise just before bedtime. It can excite our body and mind, prolonging the time it takes to fall asleep (Fig. 5.1) [8].

Figure 5.1

Exercise and sleep time (Modified from Reid KJ et al [9])


It was found that 16 weeks of moderate level exercise during daytime resulted in decreased sleep latency, increased total sleep duration, alleviated depression, and improved quality of sleep and life (Table 5.1).

Table 5.1

Effects of exercise on sleep quality, depression, and quality of life (Modified from Reid KJ et al [9])

Exercise group Non-exercise group
Sleep quality appraisal Improved No change

Depression Improved No change

Life quality appraisal Improved No change

3.2 Consumption of caffeine may worsen the quality of sleep

Consumption of caffeine before bedtime leads to decreased sleep duration, increased latency to sleep onset, and decreased deep sleep [10,11]. Caffeine consumption both 3 and 6 hours before bedtime equally reduced the total sleep time and increased the wake time during sleep (Fig. 5.2) [12]. To improve the quality of sleep, caffeinated products such as coffee and green tea are to be avoided.

Figure 5.2

Caffeine consumption and sleep

(Modified from Drake C et al [12])


3.3 Smoking reduces the quality of sleep

It tends to take more time for smokers to fall asleep, and they are also likely to wake up earlier than non-smokers. Additionally, smoking can reduce sleep quality, as it is a risk factor for sleep disordered breathing during sleep.

3.4 Drinking alcohol reduces sleep quality

The sedative effects of alcohol make one fall asleep fast, but alcohol reduces the overall quality of sleep, renders one prone to fitful sleep, and makes returning to sleep difficult once awakened [13].

Drinking sometimes helps one to fall asleep faster, but continuous drinking disturbs the state of sleep and makes one wake up often while in bed. A previous study reported that acute high-dose drinking or chronic drinking could decrease sleep latency, but disturb sleep continuity and decrease total sleep duration [14].



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[1] Contributing associations:

The Korean Academy of Sleep Medicine

Korean Neuropsychiatric Association