Definition - What does Sleep Stage 1 mean?
Stage 1 of the sleep cycle is included in the non-REM cycle of sleep, lasting for 5-15 minutes. Stage 1 is characterized by a transition between sleep and wakefulness. This is often experienced as drowsiness, such as heavy eyelids, but individuals can be easily awakened during this stage. In this stage, the brain waves begin to slow to theta waves, and eye movements and muscle activity also slow down.
SureHire explains Sleep Stage 1
Nightly sleep cycles oscillate between four stages. Each sleep stage generally lasts for 5-15 minutes, with an entire cycle taking 90-110 minutes cycling back to stage 1. It is normal for individuals to feel muscle spasms or the experience of falling when in stage 1 of the sleep cycle. In general, older individuals tend to spend more time in their sleep cycle in Stage 1 and short naps primarily exist in Stage 1 as well.