What are the stages of sleep:
There are four distinct stages of sleep, which vary in intensity and brain activity and can alternate through the course of sleep. Scientists have identified two phases of sleep that exist within these four stages: REM (Rapid Eye Movement) and NREM (Non-Rapid Eye Movement). Throughout one night’s sleep, we cycle through each of these phases repeatedly. A complete sleep cycle, from the beginning of stage one to the end of REM sleep, usually takes about one and a half hours.
Sleep research has shown that in an average sleep session, there are generally 3 equal time periods or cycles: sleep in the first third of the night, which comprises the highest percentage of NREM; sleep in the middle third of the night; and sleep in the last third of the night, the majority of which is REM. Awakening after a full night’s sleep is usually from REM sleep.
Sleep stages at different ages:
Sleep cycles tend to vary as our bodies develop and we begin to age. Infants require the most sleep of all age groups, clocking in a total sleep duration of 14-16 hours in a single day. In adults, the amount of sleep duration required per day is approximately 8 hours. This can vary from person to person though, as some adults may require only 5 hours per day while others may need 10 hours. Scientists have yet to identify the exact variables that cause this variation, but have defined sleep requirements as unique to each individual. Later in life, the overall need for sleep tends to decrease and sleep stages become lighter and more fragmented. Due to this change in sleep intensity, the amount of restorative sleep decreases and it becomes more difficult to actually fall asleep. In effect, older people may need to stay in bed longer to get the required amount of fully restorative sleep.
The information presented is for informational purposes only. Any consumer should consult their doctor, practitioner, and/or pharmacist for any health problems/questions and before using any supplements or before making any changes in prescribed medications.