Describe the impact of alcohol on sleep architecture and daytime functioning.

• A. It does not affect sleep architecture.
• B. It reduces REM sleep but improves daytime energy.
• C. It reduces REM sleep and causes daytime sleepiness.
• D. It disrupts REM sleep, fragments sleep; leads to daytime fatigue and cognitive impairment.

Answer: (D)

Alcohol disrupts the normal pattern of sleep stages. While it may help you fall asleep faster, its effects wear off during the night and sleep becomes more fragmented. It tends to suppress REM sleep and can disturb the progression through non-REM stages, especially in the second half of the night, so the brain doesn’t get the full restorative benefits REM and deep sleep provide. This fragmentation and reduced REM sleep mean sleep is less refreshing, leaving you with daytime fatigue, slower thinking, trouble concentrating, and slower reaction times. Dehydration, increased urination, and potential worsened snoring or sleep apnea can further disrupt sleep as alcohol wears off. In the morning, REM rebound can occur, leading to more awakenings and vivid dreams, which keeps overall sleep quality lower. Overall, alcohol disrupts REM sleep and fragments sleep, leading to daytime fatigue and cognitive impairment.