NREM Stage 1, accounting for 5-10% of total sleep in monophasic adults, is the lightest of all NREM Stages. During this stage, awareness to the external environment and consciousness is diminished. Some people experience hypnic jerks or hypnagogic hallucinations during this stage. A mix of [[Wikipedia:alpha waves|alpha waves]] and [[Wikipedia:theta waves|theta waves]] are present in this stage.
NREM第一階段佔單相成人總睡眠的5-10%,是所有NREM階段中最淺的睡眠階段。在這個階段中,對外部環境和對自身的意識都會有所減弱。部分人在這個階段會出現抽搐或臨睡幻覺。NREM1中Alpha波和Theta波會混合存在。