Role and Function of Sleep

Sleep is essential to humans, just like air, water and food. When necessary, people can cope without sleep for periods of time, but the longer we are awake, the stronger the urge to sleep becomes.

The exact role and function of sleep has been a topic of debate for researchers, but most agree that sleep serves a restorative purpose, both psychologically and physiologically. It is thought that delta sleep (stages 3 &4) is most involved with restoring the body and physical energy, while REM sleep is most important for restoring mental function such as memory and concentration.

Sleep is important for general physical health, restoring energy, repairing injuries or illness, growth, psychological well-being and mood, concentration, memory, work performance, and getting along with others.


Effects of Lack of Sleep

People vary in terms of how much sleep they need – while the average sleep duration for adults is 7-8.5 hours per night, some people function well with 4-5 hours and other require 9-10 hours. Whatever your individual needs, lack of sleep or poor sleep quality can have effects including:

  • Poor attention, concentration and memory
  • Irritability and other mood disturbances
  • Impaired judgment and reaction time
  • Poor physical coordination (dangerous for driving)

The seriousness of these effects depends on how bad the sleep deprivation is (e.g. less sleep vs. no sleep; one night’s poor sleep vs. chronic problems) and the tasks and responsibilities of the day. If you have ongoing problems with sleep, it is important to seek help.


How Well Do Good Sleepers Sleep?

  • Good sleepers usually take less than 30 minutes to fall asleep at the beginning of the night and will wake up once or twice during the night. In other words, it is unrealistic to expect to fall asleep immediately on getting into bed or to never wake up at all during the night. Even the best sleepers in the world don’t achieve this!
  • Also, everybody, even the best sleepers, will have a night now and then when it takes them a long time to get to sleep. This is often triggered by a stressful event and will usually pass after a night or two. Similarly, everybody will have a night now and then when they find it difficult to get back to sleep after waking up in the middle of the night.


Sleep Tips

  • Get regular.
    One of the best ways to train your body to sleep well is to go to bed and get up at more or less the same time every day, even on weekends and days off! This regular rhythm will make you feel better and will give your body something to work from.
  • Sleep when sleepy.
    Only try to sleep when you actually feel tired or sleepy, rather than spending too much time awake in bed.
  • Get up & try again.
    If you haven’t been able to get to sleep after about 20 minutes or more, get up and do something calming or boring until you feel sleepy, then return to bed and try again. Sit quietly on the couch with the lights off (bright light will tell your brain that it is time to wake up), or read something boring like the phone book. Avoid doing anything that is too stimulating or interesting, as this will wake you up even more.
  • Avoid caffeine & nicotine.
    It is best to avoid consuming any caffeine (in coffee, tea, cola drinks, chocolate, and some medications) or nicotine for at least 4-6 hours before going to bed. These substances act as stimulants and interfere with the ability to fall asleep.
  • Avoid alcohol.
    It is also best to avoid alcohol for at least 4-6 hours before going to bed. Many people believe that alcohol is relaxing and helps them to get to sleep at first, but it actually interrupts the quality of sleep.
  • Bed is for sleeping.
    Try not to use your bed for anything other than sleeping and sex, so that your body comes to associate bed with sleep. If you use your bed as a place to watch TV, eat, read, work on your laptop, pay bills, and other things, your body will not learn this connection.
  • No naps.
    It is best to avoid taking naps during the day, to make sure that you are tired at bedtime. If you can’t make it through the day without a nap, make sure it is for less than an hour and before 3pm.
  • Sleep rituals.
    You can develop your own rituals of things to remind your body that it is time to sleep – some people find it useful to do relaxing stretches or breathing exercises for 15 minutes before bed each night, or sit calmly with a cup of caffeine-free tea.
  • Bath time.
    Having a hot bath 1-2 hours before bedtime can be useful, as it will raise your body temperature, causing you to feel sleepy as your body temperature drops again. Research shows that sleepiness is associated with a drop in body temperature.
  • No clock-watching.
    Many people who struggle with sleep tend to watch the clock too much. Frequently checking the clock during the night can wake you up (especially if you turn on the light to read the time) and reinforces negative thoughts such as “Oh no, look how late it is, I’ll never get to sleep” or “it’s so early, I’ve only slept for 5 hours, this is terrible.”
  • Exercise.
    Regular exercise is a good idea to help with good sleep, but try not to do strenuous exercise in the 4 hours before bedtime. Morning walks are a great way to start the day feeling refreshed!
  • Eat right.
    A healthy, balanced diet will help you to sleep well, but timing is important. Some people find that a very empty stomach at bedtime is distracting, so it can be useful to have a light snack, but a heavy meal soon before bed can also interrupt sleep. Some people recommend a warm glass of milk, which contains tryptophan, which acts as a natural sleep inducer.
  • The right space.
    It is very important that your bed and bedroom are quiet and comfortable for sleeping. A cooler room with enough blankets to stay warm is best, and make sure you have curtains or an eye mask to block out early morning light and earplugs if there is noise outside your room.
  • Keep daytime routine the same.
    Even if you have a bad night of sleep and are tired, it is important that you try to keep your daytime activities the same as you had planned. That is, don’t avoid activities because you feel tired. This can reinforce the insomnia.
Source: Centre for Clinical Interventions