The National Sleep Foundation says that most healthy adults need seven to eight hours of sleep each night. However, basal sleep needs vary quite a bit between individuals.
WebMD says that most healthy adults need between 7.5 and 8 hours of sleep each night. It is possible that more sleep may be ideal. Surveys of adults in the 1960s and 1970s report that the average adult was sleeping 8 to 8.5 hours a night.
The National Sleep Foundation says that too-short sleep durations are linked to a number of poor health outcomes, such as increased risk of obesity, diabetes, depression and car crashes. Sleep-deprived individuals have trouble paying attention, remembering new information and staying alert.