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Losing Sleep: the Causes and Effects of Sleep Deprivation
The Case of Medical ProfessionalsOur modern health care system requires that physicians, nurses and other health care providers often need to be awake at night and work for durations well in excess of 12 hours. Chronic partial sleep deprivation is an inherent consequence of such schedules.(48) Not surprisingly, human error increases with such prolonged work schedules. Studies have also shown that such schedules are tied to an increased likelihood of motor vehicle accidents for health care providers driving home from their shifts.(49)
In 2003, the Accreditation Council for Graduate Medical Education (ACGME) imposed duty hour limits for residents. These limited residents to an 80 hour workweek and limited continuous duty periods to 24-30 hours. The ACGME also mandated that 1 out of every 7 days be free from duty, averaged over a 4-week period, and mandated 10-hour rest breaks between duty periods.(50)(51)
Treatments for Sleep DeprivationClearly, travel across time zones, prolonged work hours and work environments with irregular schedules contribute to performance problems, fatigue and safety risks. What can a person do to counteract sleep deprivation? The obvious best countermeasure for sleep deprivation is to get adequate sleep. Research suggests that the definition of what constitutes "adequate" varies from person to person.
Individuals who are sleep-deprived because of their work or travel schedules should make sure they give themselves prolonged, restorative sleep in the form of 10 to 14 hours of recovery sleep whenever they can.
A number of treatments are available for individuals who are unable to obtain adequate sleep because of medical or sleep-related conditions (e.g., narcolepsy, obstructive sleep apnea). These include:
Continuous Positive Airway PressureContinuous Positive Airway Pressure (CPAP) uses a machine to increase air pressure in your throat so that your airway does not collapse when you breathe in. It is considered the most effective treatment for obstructive sleep apnea in both middle-aged and older adults.(52) CPAP increases alertness and improves cognitive processing, memory and executive function.
ModafinilIn some patients, CPAP does not completely eliminate excessive sleepiness. For them, the stimulant drug, modafinil(53)(54) improves vigilance, general productivity and activity level. In addition, modafinil is effective in the treatment of narcolepsy(55) and excessive daytime sleepiness caused by Parkinson's Disease.(56)
CaffeineCaffeine improves alertness and vigilance, with the size of the effects increasing with caffeine dose,(57) and is as effective as modafinil.(58) Caffeine can block sleep inertia — the grogginess and disorientation that a person experiences after awakening from sleep — a fact which may explain why this common stimulant is so often used in the morning, after a night of sleep.
Bright LightExposure to bright light produces significant improvement in performance and alertness levels.(59) Light wavelength appears to play a role in such improvements. For example, in one experiment, people exposed to lower-frequency (460-nm) light had significantly lower subjective sleepiness ratings and fewer attention failures than people exposed to higher-frequency (555-nm) light.(60) In addition, light enhanced recovery from the circadian and sleep misalignments that result from jet lag, shiftwork and aging.(61)
ConclusionFatigue, sleepiness and general performance decline — including attention lapses, increased reaction times, cognitive slowing and memory difficulties — are caused by acute and chronic sleep loss and circadian displacement of sleep-wake schedules. These are common occurrences in cases where people work unusual schedules or have sleep disorders, jet lag or certain medical conditions. They increase the likelihood of cognitive errors and the risk of mistakes or accidents, although the degree of these effects varies from one person to another. Neurobehavioral and neurobiological research have demonstrated that waking functions depend upon stable alertness and that alertness, in turn, depends on adequate daily recovery sleep. Understanding and mitigating the risks imposed by physiologically-based variations in fatigue and alertness are essential for making jobs such as driving trucks, flying airplanes or practicing medicine safer, as well as for the development of effective countermeasures.
February 1, 2008
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