Sleep was long considered just a uniform block of time when you are not awake.
Thanks to sleep studies done, it is now known that sleep has distinctive stages that
cycle throughout the night. Your brain stays active throughout sleep, but different
things happen during each stage. For instance, certain stages of sleep are indeed for
us to feel well rested and energetic the next day, and other stages help us learn or
The Science of Sleep
Sleep can be divided into two types: rapid eye movement (REM) sleep and non-
REM (NREM) sleep. NREM sleep has four stages of increasingly deep sleep. Stage 1
sleep is the lightest, while stage 4 is the deepest.
Typically, people sleep at night — thanks not only to the conventions of the 9-
to-5 workday, but also to the close interaction between our natural sleep and
alertness rhythms, which are driven by an internal “clock” situated in the brain. Light
and exercise “reset” the clock and can move it forward or backward. Abnormalities
related to this clock are called Circadian Rhythm Disorders (“circa” means “about,”
and “dies” means “day”;) e.g. Jet lag, shift work (drivers, doctors, nurses, BPO
The Eight-Hour Myth
Weâ€™ve all been told that we should get eight hours of sleep per night. This
information is an average, and might not be a perfect fit for everyone. Some may need
more sleep, and others less, so it varies from person to person.
Short vs. Long Sleepers
Everyone has a sleep need that is likely determined by our genes. This need is
the amount of sleep our body requires for us to wake up feeling refreshed. This likely
occurs across a spectrum, with â€œshort-sleepersâ€ needing less than average of 8 hrs
may be 5 hrs or so and â€œlong-sleepersâ€ needing more than 8 hrs may be up to 10 hrs.
Changing Needs Across a Lifetime
The average amount of sleep needed, with individuals both above and below
these needs, changes over oneâ€™s lifetime:
â™£ Infants (3-11 months) need 14-15 hours
â™£ Toddlers (12-35 months) need 12-14 hours
â™£ Preschoolers (3-6 years) need 11-13 hours
â™£ School age (6-10 years) need 10-11 hours
â™£ Adolescents (11-18 years) need 9.25 hours
â™£ Adults need an average of 7 to 8 hours
â™£ Elderly adults may need less sleep
How Can I Determine My Sleep Needs?
There is an easy way to determine how much sleep you need. Follow these steps:
â™£ Set aside a week or two that you can focus on your sleep and not allow
disruptions or changes to your sleep schedule.
â™£ Select a typical bedtime and stick with it, night after night.
â™£ Allow yourself to sleep in as long as you want, awakening without an alarm clock
in the morning.
â™£ After a few days, you will have paid off your sleep debt, and you will begin to
approach the average amount of sleep that you need.
â™£ Once you determine your need, try to set your bedtime at an hour that will allow
you the sleep you need, while still waking up in time to start your day.
Not sleeping enough and not sleeping well is not OK. Chronic sleep deprivation
significantly affects health, safety and performance.
The stresses of daily life may intrude upon our ability to sleep well. Many
medical or mental-health conditions can disrupt sleep. However, it is critically
important to realize that sleep deprivation is very often due to unrecognized sleep
disorders. Letâ€™s look at the consequences of sleep deprivation which are short term
and long term as discussed below.
What happens if we donâ€™t meet sleep needs? By not getting enough sleep, we
accumulate a sleep debt that we usually have to â€œpay off.â€ This might involve extra
sleep by napping, going to bed early, or sleeping in to catch up. If we sleep less than
our body needs to feel refreshed and donâ€™t catch up we might experience:
â™£ Daytime sleepiness
â™£ Difficulty concentrating
â™£ Poor thinking
â™£ Increased risk of accidents
Long term – The clinical consequences of chronic untreated sleep disorders are large
indeed. They are associated with numerous, serious medical illnesses, including:
â™£ High blood pressure, Heart attack, Stroke
â™£ Mental impairment, Depression and mood disorders
â™£ Attention Deficit Disorder (ADD)
â™£ Injury from accidents
â™£ Disruption of bed partner’s sleep quality
â™£ Poor quality of life
Get a Good Night’s Sleep
All that said, here are some sleep hygiene tips to help you
relax, fall asleep, stay asleep, and get better sleep so that you
wake up refreshed and alert.
â™£ Stick to a sleep schedule. Go to bed and wake up at the same time each dayeven
on the weekends.
â™£ Exercise is great but not too late in the day. Avoid exercising closer than 5
or 6 hours before bedtime.
â™£ Avoid nicotine, caffeine and alcohol in the evening. The stimulating effects
of caffeine in coffee, colas, teas, and chocolate can take as long as 8 hours to
wear off fully. Nicotine is also a stimulant. Alcohol keeps you in the lights
stages of sleep. You also tend to wake up in the middle of the night when the
sedating effects have worn off.
â™£ Avoid large meals and beverages late at night. A large meal can cause
indigestion that interferes with sleep. Drinking too many fluids at night can
cause you to awaken frequently to urinate.
â™£ Eat right, sleep tight. Try not to go to bed hungry, but avoid heavy meals
before bedtime. Some foods can help, though. Milk contains tryptophan, which
is a sleep-promoting substance. Other foods that may help promote sleep
include almonds, peaches, walnuts, apricots, oats, asparagus, potatoes, pumpkin,
avocados, eggs and bananas.
â™£ Avoid medicines that delay or disrupt your sleep, if possible. Some
commonly prescribed heart, blood pressure, or asthma medications, as well as
some over-the-counter herbal remedies for coughs, colds, or allergies, can
disrupt sleep patterns.
â™£ Don’t take naps after 3 p.m. Naps can boost your brain power, but late
afternoon naps can make it harder to fall asleep at night. Also keep your naps to
15 to 30 minutes.
â™£ Relax before bed. Take time to unwind. A relaxing activity, such as reading or
listening to music, should be part of your bedtime ritual.
â™£ Take a hot bath before bed. The drop in body temperature after the bath
may help you feel sleepy and the bath can help relax you.
â™£ Have a good sleeping environment. Get rid of anything that might distract you
from sleep, such as noises, bright lights, an uncomfortable bed, or a TV or
computer in the bedroom. Also, keeping the temperature in your bedroom on the
cool side can help you sleep better.
â™£ Don’t lie in bed awake. If you find yourself still awake after staying in bed
for more than 20 minutes, get up and do a quiet relaxing activity such as
reading or listening to music until you feel sleepy. The anxiety of not being able
to sleep can make it harder to fall asleep.
â™£ Keep pets off the bed. Does your pet sleep with you? This, too, may cause you
to awaken during the night, either from allergies or pet movements. Fido and
Fluffy might be better off on the floor than on your sheets.
â™£ See a doctor if you continue to have trouble sleeping. If you consistently
find yourself feeling tired or not well rested during the day despite spending
enough time in bed at night, you may have a sleep disorder. Your family doctor
or a sleep specialist should be able to help you.
Compiled by Medical & Occupational Health Centre, RCP.