Understanding Sleep and Stages of Sleep
We spend one-third of our lifetime sleeping! Sleep is not a waste of time and we must
allot adequate time for sleeping even if we have many important jobs to do. Sleep
is as important as food and water for our survival. Getting enough quality
sleep at the right time is very essential for leading a healthy life. Sleep
is important for a number of brain functions. Sleep is a complex and dynamic
process that plays a housekeeping role. During sleep tissues are repaired and
toxins are removed from the brain and other organs. Sleep affects all
tissues and systems in the body including metabolism, immune function, mood and
performance. Chronic lack of sleep or poor-quality sleep, increases the
risk of disorders like hypertension, diabetes, obesity and depression.
Sleep mechanisms
Two internal biological mechanisms–circadian
rhythm and homeostasis regulate sleep-wake patterns.
Circadian rhythms are
controlled by the body’s clock and is in harmony with sunrise and sunset in a
24 hours day. They also synchronize with other environmental cues like light
and temperature and direct a wide variety of functions including timely wakefulness,
metabolism, and the release of hormones.
Sleep-wake homeostasis keeps
track of our need for sleep. The homeostatic sleep drive reminds the body
to sleep after a certain period of sleep deprivation and regulates sleep
intensity and quality. Sleep-wake homeostasis is greatly influenced by
exposure to light. Exposure to light reduces sleep. Other influencing
factors are diseases, medications, stress, sleep environment and diet.
Night shift workers and late night party goers often have
trouble falling asleep. They also have trouble staying awake at work because
their natural circadian rhythm and sleep-wake cycle is disrupted.
Sleep Stages
There are basically two types of sleep. Non rapid eye movement (NREM) sleep having three stages, and rapid eye movement (REM) sleep. They
are linked to specific brain waves and neuronal activity. We cycle through all stages of non-REM and
REM sleep 4-5 times during a typical night. As the advances the REM periods are
increasingly longer, with deeper REM periods occurring towards morning.
Stage 1 non-REM sleep
is the changeover from wakefulness to sleep. During this short period
(lasting several minutes) of relatively light sleep, our heartbeat, breathing,
and eye movements slow, and our muscles relax with occasional twitches. Our
brain waves begin to slow from their daytime wakefulness patterns.
Stage 2 non-REM sleep
is a period of light sleep before we enter deeper sleep. Our heartbeat
and breathing slows down and muscles relax even further. Our body
temperature drops and eye movements stop. Brain wave activity slows but
is marked by brief bursts of electrical activity. We spend more of our
repeated sleep cycles in stage 2 sleep than in other sleep stages.
Stage 3 non-REM sleep
is the period of deep sleep that we
need to feel refreshed in the morning. It occurs in longer periods during
the first half of the night. Our heartbeat and breathing slow down to
their lowest levels during sleep. Our muscles are relaxed and our brain
waves become even slower.
REM
sleep first occurs about 90 minutes after falling asleep. Our eyes
move rapidly from side to side behind closed eyelids. Mixed frequency
brain wave activity becomes closer to that seen in wakefulness. Your
breathing becomes faster and irregular, and your heart rate and blood pressure
increase to near waking levels. Most of your dreaming occurs during REM
sleep, although some can also occur in non-REM sleep. Your arm and leg
muscles become temporarily paralyzed, which prevents you from acting out your
dreams. As you age, you sleep less of your time in REM sleep.
Memory consolidation most likely requires both non-REM and REM sleep.
Tips for getting enough
Quality Sleep
Getting enough quality sleep
is absolutely essential for long term good health. A few important tips to
improve quality sleep are given below:
1.
Make it a habit
to sleep at the same time every night and wake up at the same time each day.
2.
Get sufficient exercise during the day, at least a
few hours before your sleeping time.
3.
Avoid caffeine and nicotine late in the day and
alcoholic drinks before bed.
4.
Eat a moderate dinner. Avoid starving.
5.
Practice relaxation methods before going to bed. A
warm bath, reading, meditation, positive affirmations or other relaxing routines.
6.
Avoid bright lights and sounds in the bedroom.
Seek professional help if you continue to have disturbed sleep
despite using the above measures.
Source : NIH – National Institute of Neurological Disorders and
Stroke
Prolong
Youth by leading an ‘enlightened
and balanced life’
Disclaimer
Body
Satva Essentials’ Team has taken maximum care to ensure authenticity of the
information provided, by sourcing from reputed medical journals and books. Body
Satva Essentials’ Team urges members to seek professional advice before
commencing any regimen of diet, exercise and medication. 
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