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Normal Sleep


Patient Information Brochure


 

How much sleep do you need?

Humans adapt to the 24-hour cycles of light and dark in the environment using their internal biological clocks (see Human Circadian Rhythms). Adults have one major episode of sleep each night that typically lasts 7.5 to 8 hours on average but can range between 6 to 9 hours in some individuals. Each person must determine his or her own nightly sleep need. You can determine this ideal amount of sleep by simply paying attention to whether or not you feel rested in the morning and alert throughout the day. If no amount of sleep will make you feel rested on the next day, then you may want to seek medical advice, including being be evaluated for a sleep disorder. People tend to sleep longer on weekends; this may be because there is more spare time to do so, or it may be due to accumulated sleep debt during the prior week. It is important to understand that you cannot "catch up" on lost sleep, or store sleep for the future, by getting more on weekends. This is because lost sleep on any given night has immediate consequences for the very next day, such as work or school performance and driving safety. Getting the sleep you need is important for optimal learning, productivity, safety, and health.

What is a typical night of sleep?

The depth and character of sleep change in a predictable manner across the night. Healthy, young adults will fall asleep in 10-20 minutes. Thereafter, the sleeper will cycle through different stages of sleep over the course of the night. As you fall asleep, your thoughts begin to wander and your awareness of the outside world is reduced - this is called Stage 1 sleep. More than half of the night is spent in Stage 2 sleep, a relatively light stage of sleep from which it is easy to awaken the sleeper. The deepest sleep (also called Slow Wave Sleep because the EEG waves are slow and large) occurs predominately in the first half of the night. Together, Stages 1, 2 and Slow Wave sleep are referred to as non-REM sleep. REM sleep (or Rapid Eye-Movement sleep) will occur approximately every 90 minutes throughout the night. You can thus expect to experience 4-5 REM sleep episodes per night. The first REM period is typically very brief, lasting less than 10 minutes, while the final episode may continue for more than an hour. This means that you get most of your REM sleep during the early morning. REM sleep is commonly associated with dreaming because your most vivid and bizarre dream reports occur during this stage of sleep, although dreaming or mental imagery takes place in all stages of sleep (see Dreams and Nightmares). Normal sleep includes several brief awakenings throughout the night.

How does sleep change across the lifespan?

The timing and duration of sleep change dramatically as we age. A newborn baby may sleep as much as 16 hours per day (see Sleep in Children). Adolescents will sleep 9 hours on average although they prefer to go to bed later and wake up later than the adults. This shift to a later sleep time is a normal pattern for teens; however, their school schedules preclude this desired pattern and as a result many teens are chronically sleep deprived. Sleep in adults can be quite organized and efficient, meaning that they sleep at regular clock times, fall asleep quickly, and have very little wakefulness during the night; however, lifestyle factors and poor sleep habits can grossly disrupt sleep in otherwise healthy adults. Shift workers experience unique problems with sleep because they are required to switch often between day and night work and sleep schedules (see Strategies for Shiftworkers). During later life, sleep becomes shorter in duration (about 6 hours on average), there is less time spent in deep sleep, arousals during the night are more frequent and for longer periods of time, and there is a tendency to nap during the day (see Sleep and Aging). Older adults prefer to go to bed earlier and wake up earlier. This shift to an earlier sleep time is a normal pattern for older adults. Just as the teenager does not stay in bed later because they are lazy, the older adult does not go to bed earlier for lack of anything better to do with their time – the timing of when we sleep and when we wake is governed by our internal circadian clocks. If you find that you are sleeping less at night than you used to, yet your daytime functioning is not impaired, then there may be no cause for concern about these changing sleep patterns.

What are the consequences of insufficient sleep?

Insufficient sleep, even on a single night, has a number of immediate consequences including lower alertness, negative mood, reduced motor and visual acuity, longer response times, and impaired attention and memory. Chronic sleep restriction over days and weeks leads to cumulative deficits in alertness, mood and cognitive performance. As well, insufficient sleep can have long-term consequences for health including weight gain, diabetes, and heart disease.

Is daytime napping good for you?

Daytime napping is natural for most toddlers. In school aged children, sleep begins to occur in a single nighttime episode and this pattern continues throughout adulthood. Napping behaviour is usually put aside until retirement age, but some people continue to enjoy regular naps throughout their lifespan. Naps are generally only a good idea for people who have no difficulty falling asleep or staying asleep at night (see Insomnia). Otherwise, the time you spend napping during the day may take away from your total sleep time at night. The optimal duration for a nap, whether during the daytime or while on the job for shift workers, is about 10-20 minutes. Twenty minutes is sufficient to feel rested, yet short enough not to interfere with nighttime sleep or your alertness on the job upon awakening. If you cannot get through the day without a long nap, despite also sleeping long hours at night, you should be evaluated for a sleep disorder (see Patient Information).

Tips for a good night’s sleep

1. Make time for sleep

Make sleep a priority in your life; sleep is just as important as diet and exercise for a healthy lifestyle. In today’s busy world, too many people simply do not make the time for sleep. Are you allowing yourself enough time in bed to get the sleep you need? It is a good idea to keep track of how much sleep you are getting by keeping a "sleep diary" (see below).

2. Keep a regular sleep schedule

As a general rule you should strive to keep a regular sleep/wake schedule, getting up at the same time each morning, 7 days per week. If you are experiencing difficulty sleeping at night, then a strict schedule becomes even more important.

3. Set the stage for sleep

Establish a comfortable sleep environment with limited distractions from noise and light, and an optimal room temperature. Immediately before bed, establish a relaxing bedtime routine, and avoid stress or use of electronic devices. Also, avoid substances with stimulants too close to bedtime (including foods, caffeinated beverages, medications, and nicotine). Note that too much alcohol in the evening may disrupt your sleep later in the night by causing early morning awakenings. Regular exercise can be good for sleep, but do so around midday or early afternoon to avoid disrupting sleep. As well, avoid long naps or naps in late afternoon and evening, and avoid heavy meals and fluids taken too close to bedtime. Lastly, save the bedroom for sleep and intimacy – do not eat, read, or watch television in bed.

Additional Resource: Sleep Diary

Use a Sleep Diary to help track your sleep habits!

 

Authored by:
Kimberly Cote, PhD,
Department of Psychology,
Brock University