Sleep disorders are common in the elderly population, with up to half complaining about sleep problems. Common causes include psychological stressors like retirement or bereavement. Age-related changes include falling asleep earlier, waking earlier, and less tolerance for changes in sleep-wake cycles. The most common disorders are insomnia and sleep apnea, characterized by frequent nighttime awakenings, early morning waking, daytime fatigue, and difficulty concentrating. Morbidity increases in sleep apnea if episodes occur more than 10 times per hour. Polysomnography and CPAP are used to diagnose and treat sleep apnea.