The point in that cycle (light sleep deep sleep and REM sleep) at which you wake can affect how you feel later and may even have a greater impact than how much or little you have slept.

你醒来的那个循环点（轻睡、熟睡、REM睡）会影响你之后的感觉，其影响甚至比你睡觉的长短还大。

youdao

Don't smoke which often leads to light sleep and reduced amounts of REM sleep.

抽烟会导致浅睡并较少深度睡眠的时间，所以不要抽烟。

youdao

Avoid alcohol consumption which keeps people in a light sleep stage and reduces one's ability to reach REM sleep stages.

喝酒会使人浅睡并减弱完成深层睡眠的能力，所以不要喝酒。

youdao

In one experiment, Oldis and another colleague named Marjorie Kaye had both entered REM sleep, when the program turned on the red light bulb cue for Oldis.

FORBES: Saying 'Hi' Through A Dream: How The Internet Could Make Sleeping More Social

Special exhibits are housed in Rem Koolhaas' high-tech "black box" structure, which allows no outside light to penetrate.

FORBES: Art and Seoul