Each is broken down into multiple stages. Non-REM sleep is referred to as stages N1, N2, and N3. A typical Non-REM cycle lasts approximately 90-120 minutes. In the first stage known as N1, a person is considered to be in the transitional phase between being alert and being drowsy. During this time, it is not uncommon to feel a sudden drifting or floating sensation. Additionally, this stage of sleep is also accompanied by sudden muscle contractions and the sensation of falling called hypnic myoclonia. The N1 stage of sleep is characterized as a very light sleep lasting only about 10-12 minutes. During this time, alpha activity will commonly appear on the EEG with eye closure [book pg 263]. Beta, vertex, and most commonly, theta waveforms may also be distinguished by electrocephalograms. Minute ventilation, heart rate, and blood pressure slowly begin to decrease in this stage on Non-REM sleep, while slow-rolling eye movements may be recorded by the electro-oculogram. In addition, muscle activity has slowed in comparison to being in a period of
Each is broken down into multiple stages. Non-REM sleep is referred to as stages N1, N2, and N3. A typical Non-REM cycle lasts approximately 90-120 minutes. In the first stage known as N1, a person is considered to be in the transitional phase between being alert and being drowsy. During this time, it is not uncommon to feel a sudden drifting or floating sensation. Additionally, this stage of sleep is also accompanied by sudden muscle contractions and the sensation of falling called hypnic myoclonia. The N1 stage of sleep is characterized as a very light sleep lasting only about 10-12 minutes. During this time, alpha activity will commonly appear on the EEG with eye closure [book pg 263]. Beta, vertex, and most commonly, theta waveforms may also be distinguished by electrocephalograms. Minute ventilation, heart rate, and blood pressure slowly begin to decrease in this stage on Non-REM sleep, while slow-rolling eye movements may be recorded by the electro-oculogram. In addition, muscle activity has slowed in comparison to being in a period of