The need for sleep varies between individuals and across the life span as we age. Normally, adults sleep from about 8.25 hours per night; we spend one-quarter to one-third of our lives asleep1. Sleep is not just the absence of wakefulness — rather, it is a complex and multi-dimensional state. Sleep influences all major systems of the body (see “The Physiology of Sleep”). And, this relationship is bi-directional, with many of body systems also influencing a person’s sleep. Sleep deprivation can drastically change an individual’s thinking and behavior and negatively impact their physical, mental, and emotional health.
- National Sleep Foundation (NSF), The Five Clusters of Sleep Patterns, Arlington: NSF, Available online at: http://sleepfoundation.org/sleep-news/five-clusters-sleep-patterns.