The
experience of being sleepy during the day from time to time is
almost universal. However, being sleepy during the day is a problem
when it happens often or every day and interferes with quality
of life. There are many causes for chronic excessive sleepiness,
such as poor sleep habits, medication side-effects, sleep disorders
and other medical conditions. It is important to identify the
specific cause(s) of an individual’s sleepiness in order
to correct the problem.
Not Enough Sleep
Most human adults require an average of eight hours of sleep per
night in order to be rested. The circumstances of our lives, however,
often prevent us from obtaining a healthy amount of sleep every
night. As we deprive ourselves of one or two hours some nights
during a week, we create a sleep deficit which results in daytime
sleepiness.
Abnormal Sleep
While we do not fully understand all that sleep does for us, it
is clear that our bodies require adequate sleep time and quality
to maintain health. The brain works hard while we sleep, going
through a series of processes that restore our feeling of alertness
and sense of well-being. When these processes are interrupted,
the result is daytime fatigue.
Most of the known sleep disorders cause disruption of the sleep
processes. Examples of such sleep disorders are Obstructive
Sleep Apnea and Periodic Limb Movements.
An overnight sleep study, or polysomnogram, is required to diagnose
and/or rule out the presence of sleep disorders that disrupt sleep.
Illness and Injury
Short and long term illness will cause excessive daytime sleepiness
and fatigue. The pain experienced because of injuries and illness
can disrupt sleep just as a sleep disorder does. Disrupted sleep,
no matter what the cause, results in daytime sleepiness. Significant
head trauma and neurological conditions may also result in excessive
sleepiness.
Medications
There are many medications which are known to cause excessive
sleepiness. Some can cause sleep apnea, which in turn causes daytime
sleepiness. Simply stopping or changing the medication can result
in improvement. However, when stopping or changing the drug is
not an option, there are additional medications available that
may help with the sleepiness.
Narcolepsy
Narcolepsy is a very specific medical disorder which causes excessive
daytime sleepiness. This disorder is caused by a deficiency in
a neuropeptide in the brain called hypocretin. Another symptom
produced by this deficiency is episodic weakness. Narcolepsy is
treated with medication and must be diagnosed via a special “sleep”
test conducted during the day.
Idiopathic (no one knows)
Sometimes none of the above problems are the cause of a person’s
excessive daytime sleepiness. When a cause cannot be determined,
the disorder is called “idiopathic”. In many cases
idiopathic sleepiness can be improved with certain treatments
even though the primary cause is never recognized.
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"Sleep And Its
