It is believed that both the Three Mile Island nuclear power plant incident and the Exxon Valdez grounding were due, at least in part, to sleep-deprived personnel. Some people, most commonly young adults, find it almost impossible to fall asleep until very late and then have trouble getting up in the morning. This syndrome can conflict with work or school schedules and lead to poor performance due to lack of sleep. This syndrome typically affects older people, leading them to fall asleep unusually early, sometimes even in the afternoon, and then wake very early, often in the middle of the night. ASPS generally causes fewer problems than DSPS, but it can seriously impair one's ability to function well during the evening hours.
Some people suffer from a fluctuating cycle that leads to irregular sleep patterns.
This can result in symptoms similar to those associated with jet lag. Others seem to lack the normal natural cycle, napping at irregular intervals throughout a 24 hour period. Aging Aging makes sleep more fragile, even in healthy older people. Often sleep comes more slowly and is more easily disrupted by noise, light, or trips to the bathroom. This may result in frequent dozing during the day, to compensate for restless nights.