If sleep is cut short the body doesn’t have time to complete all the phases needed for muscle repair, memory consolidation and release of hormones regulating growth and appetite; you may wake up less prepared to concentrate or make decisions. Furthermore, lack of adequate sleep leads to a myriad of negative effects; it affects your health and could lead to the development of type 2 diabetes by changing the way your body processes glucose, sleep deprivation makes you irritable and chronic sleep debt can lead to mood disorders such as anxiety and depression among others.

The bottom line is, when you don’t sleep well, you don’t live well.

Sleep architecture follows alternating patterns of REM and non REM throughout a typical night which repeats itself about every 90 minutes. For 75 percent of the night, your body is in non REM sleep which is composed of four stages. Stage one consists of light sleep, stage two is the onset of sleep where we become disengaged from our surroundings; three and four entail the most involving part of sleep with tissue growth, growth hormone release, muscle relaxation and energy restoration. REM sleep which takes up 25 percent first occurs about 90 minutes after falling asleep recurring every 90 minutes getting longer later in the sleep cycle; REM provides energy to the body.

Source: Health Guide 911