The Five Stages of Sleep
Stage 1 – Drowsy
Stage 1 is state of drowsiness. It is the transition between wakefulness and sleep. It represents only 2% to 5% of your total sleep.Your brain produces slow brain waves and your muscle and brain activity slows down. You can experience slow eye movements and occasional muscle twitching commonly known as “hypnic jerks.” It is easily interrupted and you are not fully asleep. According to Saatva, If you’re woken up during this sleep stage, you might feel like you haven’t slept at all.
Stage 2 – Light Sleep
Stage 2 is the Light Sleep phase. It represents 45% to 55% of daily sleep. In order the protect your brain from awakening from sleep, it produces rythmic brain waves called “sleep spindles” intermixed with sleep structures known as “K complexes.” Your body temperature decreases and your heart rate begins to slow down.
Stage 3 – Moderate Sleep
Stage 3 is the Moderate Sleep Phase. It is the transitional period before the “deep sleep” phase. It represents 3% to 8% of your total sleep. Your brain starts to produce slower brain waves called “delta waves.” Awakenings and arousals are rare. According to Saatva, older adults have trouble entering a state of deep sleep—they also tend to sleep less and wake up more often.
Stage 4 – Deep Sleep
Stage 4 is the “deep sleep” phase. It represents 10% to 15% of the daily sleep. The brain continues to produce “delta waves.” You will experience breathing and limited muscle activity. Sleepwalking and bed wetting can occur during this phase. According to Saatva, tissue repair happens during deep sleep, as does the release of hormones, such as growth hormone (which is needed for growth and development)
Stage 5 – REM Sleep
Stage 5 is the Rapid Eye Movement (REM) phase. It represents 20% to 25% of the daily sleep. Eye movements are rapid, moving from side to side and brainwaves start to speed. Dreaming occurs during the REM sleep phase. Your muscles will relax and your heart rate will increase. Breathing becomes more rapid and shallow. Awakenings and arousals are more common during REM sleep and can result in a feeling of weakness or groginess.