top of page

Wake up refreshed and full of energy

Have you ever woken up in the middle of the night and were completely awake? While usually when alarm clock wakes you up in the morning you feel sleepy, tired and cranky? The reason is you woke up during different sleep stages. We know 4 stages of sleep: Light NREM stage, NREM stage, Deep NREM stage and REM stage. In light stage person is nearly awake, in NREM stage you are going into a

deeper sleep, heart and breathing rate decreases and body temperature lowers, next stage is deep sleep when the body regenerates the most, REM stage has the highest brain activity while the body remains relaxed. Waking up in REM or deep stage will make you tired and sleepy, while if you wake up in light stage you will feel fresh and full of energy. Stages rotate in sleep cycles which last from 90-
120min and are getting shorter in the morning hours. Somni sleep system tracks your heartbeat, breathing and movements and can determine your sleep stage in real time – therefore can wake you up in the appropriate stage. How this works – you set up a time when you need to wake up at latest,
Somni sleep system tracks and predicts your sleep cycle and wakes you up at the light stage closest to the desired wake up time.


Stage 1 is the lightest stage of NREM sleep. Often defined by the presence of slow eye movements,this drowsy sleep stage can be easily disrupted causing awakenings or arousals. Muscle tonethroughout the body relaxes and brain wave activity begins to slow from that of wake. Occasionallypeople may experience hypnic jerks or abrupt muscle spasms and may even experience sensation offalling while drifting in and out of Stage 1.

NREM Alpha Brain Waves

2          4          6         8          10         12         14          16         18          20

Time (seconds)

Stage 2 is the first actual stage of defined NREM sleep. Awakenings or arousals do not occur as easily as in Stage 1 sleep and the slow moving eye rolls discontinue. Brain waves continue to slow with specific bursts of rapid activity known as sleep spindles intermixed with sleep structures known as K complexes. Both sleep spindles and K complexes are thought to serve as protection for the brain from awakening from sleep. Body temperature begins to decrease and heart rate begins to slow.

NREM Theta Brain Waves (sleep spindles; K-complexes)

2          4          6         8          10         12         14          16         18          20

Time (seconds)

Stage 3 is known as deep NREM sleep. The most restorative stage of sleep, stage 3 consists of delta waves or slow waves. Awakenings or arousals are rare and often it is difficult to awaken someone in Stage 3 sleep. Parasomnias (sleepwalking, sleep talking or somniloquy and night terrors) occur during the deepest stage of sleep.

NREM Delta Brain Waves

2          4          6         8          10         12         14          16         18          20

Time (seconds)

REM sleep, also known as rapid eye movement, is most commonly known as the dreaming stage. Eye movements are rapid, moving from side to side and brain waves are more active than in Stages 2 & 3 of sleep. Awakenings and arousals can occur more easily in REM; being woken during a REM period can leave one feeling groggy or overly sleepy.

REM State Brain Waves

2          4          6         8          10         12         14          16         18          20

Time (seconds)
bottom of page