The elderly have increased sleep problems. First, there is the belief that one should sleep. Older adults need less hours of sleep, i.e. five to seven hours, so their expectations get frustrated if they keep trying to sleep eight hours. Secondly, the elderly have a higher prevalence of disruptive symptoms for sleep: joint pain, night urination, and so on. On the other hand, they usually take more drugs for high blood pressure, cholesterol, etc., and some may induce insomnia. The elderly have greater prevalence of sleep disorders, including restless legs syndrome, apnea, etc. and therefore a higher probability of poor sleep. The elderly may also be afraid of dying during sleep, which causes insomnia.