Geting a good night's sleep is crucial to health and longevity. However, insomnia and related disorders of the sleep-wake cycle all too common. This cycle--which is about 25 hours on average--governs the flow of neurotransmitters in the brain, making sure the body can rest and recuperate. Disturbances in the sleep-wake cycle are caused by lifestyle factors or medical conditions.
Lifestyle Factors
Several sleep-wake disorders are caused by certain lifestyle factors associated with modern living. The sleep-wake cycle, known as the circadian rhythm, is sensitive to light. When we change the time we are exposed to light, either by electric light at night or by traveling far distances, the circadian rhythm loses the beat. Jet lag is a common sleep disorder that is initiated by traveling to new time zones. In general, traveling east is more problematic because the time to sleep is advanced. It is easier to recuperate from traveling west because the circadian rhythm is not as badly compromised by a sleep delay. The Centers for Disease Control recommends not drinking coffee while traveling, which can make jet lag worse no matter what your destination.
Shift work can also disrupt the sleep-wake cycle, causing insomnia and restlessness during down times, and sleepiness and lethargy during awake hours. Working the night shift is more easy to adjust to than swing shifts; when working swing shifts, times for sleep constantly change.
Internal Disorders of the Sleep Wake Cycle
Delayed Sleep Phase Syndrome (DSPS) is a sleep-wake disorder caused by internal, rather than external, factors. This is a type of insomnia that is characterized by difficulty in getting to sleep at the desired time, and trouble waking up in the morning. DPSP is strongly associated with depression, and may continue for years after adolescence. Stanford University professor William Dement suggests that bright-light therapy is one effective treatment. This treatment simply strengthens the circadian rhythm with exposure to bright light in the mornings, and avoidance of light in the evening.
A similar condition to DSPS is Advanced Sleep Phase Syndrome (ASPS), which is characterized by early morning awakening. Like DSPS, it can be treated with bright-light therapy and also chronotherapy treatments that routinize sleep schedules by delaying sleep for 3-hour increments until the desired sleep time is met.
Non-24-Hour Sleep-Wake Syndrome
Other sufferers of insomnia do not conform to either night wakefulness or morning sleepiness patterns, but instead have more erratic sleep issues. Those who suffer from the Non-24-hour sleep-wake syndrome have circadian rhythms that do not conform at all to the 24-hour day. Rather, the wakefulness time extends each day, so that every day the sleeper wakes up a little later than the day before. Some people who naturally find themselves awake at night and sleepy during the day claim that they function much better at night. One "night owl," author George Dawes Green, stated that when treated for his condition, he never felt as creative as when he "let himself go."
