The truth is there is no exact science to say exactly how much or how little sleep we should be getting. There is a recommended 8 hours, but that differs up or down depending on age, and is really just a recommended median in a window of time rather than an exact number.
It is often hard once we lay our heads on the pillow to wind down and to enter into the first stages of sleep. We get too distracted with external lights and electronic devices that it takes more time to unwind. There are four stages of sleep. The first being a very surface phase which people can be easily woken from. In stage two eye movement and brain waves start to slow, in stage three we enter what is called a delta or very deep sleep, and lastly Rapid Eye Movement or REM is the final stage. In REM we start to come out of the delta sleep and the cycle starts again.
An article on Sleepdex says, “Infants spend almost 50% of their time in REM sleep. Adults spend nearly half of sleep time in stage 2, about 20% in REM and the other 30% is divided between the other two stages. Older adults spend progressively less time in REM sleep.” This parallels the information from the NSP that shows a gradual scale from infancy to adulthood lessening the amount of recommended sleep.
All of these results are from studies and tests that were done, but I think the real results come from listening to our own bodies. There are nights when five hours suffice and others when twelve hours are perfect. In truth there is no exact number for just how little or how much sleep we need. How many hours do you get a night and do you consider it enough? Read more on the National Sleep Foundations website HERE