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Problem Sleepiness
A brief description
Experiencing sleepiness at inappropriate times is not a
normal condition. Sleepy individuals exhibit impairment, ranging from poor functioning at
home, school, or work to potentially life-threatening automobile crashes and industrial
accidents. Performance deficits occur in all sleepy people, regardless of their education,
occupation, or motivation to remain awake. Patients with problem sleepiness may complain
of difficulty concentrating, fatigue, and emotional lability. Problem sleepiness
occurs when the quantity of sleep is inadequate due to primary sleep disorders, other
medical conditions, or lifestyle factors.
Causes of problem sleepiness
For all people, sleepiness is physiologically regulated
by two primary processes:
The body's circadian rhythm causes an
increase in sleepiness twice during a 24- hour period (in general, between midnight and 7
a.m. and in the mid-afternoon between 1 p.m. and 4 p.m.) and
The physiological need for sleep, which is
increased by sleep loss and sleep disruption
The need for sleep and the circadian rhythm interact to
determine the level of sleepiness and alertness. People with disturbances of either
of these sleep-regulating mechanisms can exhibit problem sleepiness, with the most common
causes being primary sleep disorders, other medical conditions that disrupt sleep, drugs,
and lifestyle.
The effects of drugs that disrupt sleep
Prescription and over-the-counter drugs, as well as
caffeine, alcohol, and nicotine, can have substantial effects on sleep and sleepiness. For
example, long-acting benzodiazepines have residual sedative effects that contribute to
daytime sleepiness; beta-blockers can cause difficulty falling asleep and increase
the number of awakenings; and theophylline has been shown to disrupt sleep in some people
even at low therapeutic doses.
Caffeine can fragment sleep. The half-life
of caffeine is between three and seven hours, so even coffee consumed during the day may
be an important cause of sleeplessness at night and sleepiness the next day. While alcohol
shortens the time it takes to fall asleep and is often ingested by patients for this
reason, it increases sleep disruption in the latter part of the night. Nicotine can
disrupt sleep and reduce total sleep time. Smokers report significantly more daytime
sleepiness and minor accidents than do nonsmokers, especially in younger age groups.
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