ARLINGTON, VA.–Approximately 40 million Americans are affected by sleep disorders, and more than 100,000 motor vehicle accidents per year are sleep related, Teodor Postolache, M.D., said at the annual conference of the Academy of Organizational and Occupational Psychiatry.
An understanding of the biologic rhythms that are associated with disruptive sleep gives psychiatrists additional perspectives on occupational problems.
Inadequate sleep, for example, could trigger a manic episode in a bipolar disorder patient, which could lead to a confrontation at work and the loss of a job, said Dr. Postolache of the University of Maryland, Baltimore.
Biologic rhythms are based on the movement of the earth and sun. They are internally generated–they occur in anticipation of environmental conditions–and circadian rhythms are the biologic rhythms based on a 24-hour cycle, explained Dr. Postolache, who specializes in consulting with travelers and athletes about aligning circadian rhythms to maximize physical and mental performance on arrival.
“One of the major roles of the circadian system is to consolidate periods of wakefulness and sleep,” as opposed to sleeping and waking several times during the day, he said. As people become sleepier, the circadian system sends signals to maintain alertness.
The circadian system raises the threshold for sleep in the evening, when sleepiness is at a maximum, and lowers that threshold in the early morning hours.
However, biologic rhythms vary with the individual, and laboratory research has shown that individual biologic rhythms impact cognitive performance. Psychiatrists–especially occupational psychiatrists–should keep this in mind.
Some people are “short sleepers” whose cognition does not improve if they sleep more than 7 or 8 hours, while others are “long sleepers” who truly need 10 hours of sleep to function at their best, Dr. Postolache said. Strategies that are aimed at helping sleep-disturbed patients get in tune with their biologic rhythms include taking naps and using light boxes and melatonin.
Naps
A 1-hour nap has been shown to pay back as much as 4 hours of sleep debt. As a result, naps should be seen as a drug-free intervention for sleepiness, and certain conditions make them more effective.
Silence and darkness are key for quality naps, as is elevation of the feet, and the hands and feet should be comfortably warm. For some people, soothing music facilitates a nap, according to Dr. Postolache.
One caveat, however, is a “terrible drop in vigilance” immediately following a nap, he said. Known as sleep inertia, this period lasts an average of 15–20 minutes, but can last up to 2 hours in rare cases.
In fact, studies have shown that hospital residents are prone to making major mistakes during the first 15–20 minutes after a nap.
From an occupational standpoint, those people who take naps at work should be given simple tasks to do when they first awaken.
“Those 20 minutes after waking up should not be a time when someone should be required to make major life or business decisions,” Dr. Postolache said.
Light boxes
Available in various forms and sizes, they help travelers shift their biologic rhythms to function at their best. Light boxes also may ease the discomfort of shift workers who are changing from a night shift to a day shift.
Melatonin
It is secreted in the dark, promotes sleepiness, and has been used to measure circadian rhythms. An onset of melatonin secretion occurs in the evening, followed by a rapid rise and then a plateau during the night.
The duration of melatonin secretion lengthens when the nights are long and shrinks when nights are short, he said.
Evidence for melatonin as a sleep agent is weak, but some evidence supports its use to reduce jet lag. A Cochrane Review (Cochrane Database Syst. Rev. 2002;2:CD001520) suggested that melatonin can relieve jet lag in people with a history of jet lag who are flying east (CLINICAL PSYCHIATRY NEWS, October 2004, p. 63).
Side effects of melatonin include drowsiness, decreased attention, GI symptoms, and possible antigonadal steroid effects, and it should be used on an as-needed basis, Dr. Postolache noted.