After having a drink or two (or three or four), sleep seems to come more easily. Alcohol makes us drowsy and we are able to fall asleep as soon as our heads hit the pillow. This sensation facilitates the well-known practice of drinking a "nightcap" at the end of a rough day.
Unfortunately, too much alcohol before bed can mean anything but "sweet dreams."
According to the NIH's Sleep, Sleepiness and Alcohol Use, while alcoholic beverages aid in both falling asleep and reaching slow-wave sleep, they can disrupt our precious rapid eye movement (REM) sleep cycles. REM sleep (the stage when we are most likely to dream) accounts for roughly 20% of a typical night's rest. When we never reach this point in the cycle, our sleep is fragmented and we wake up with our bodies sleepy, our concentration poor, and our memory diminished. The more you drink, the more this cycle is disrupted.
Beyond disrupting our REM cycle, alcohol impacts other aspects of sleep. Since it is a diuretic, alcohol makes you use the restroom more often during the night and leaves you dehydrated. Additionally, since your muscles are in a more relaxed state, breathing-related problems are exacerbated. This means that, on a smaller scale, snoring is louder and, more seriously, sleep apnea sufferers potentially go without breathing for longer periods of time.
Fortunately, moderate drinking (1-2 drinks) with plenty of time before bed (at least a few hours) has a much less significant impact on our sleep. Be sure to give your body some time to process the alcohol before hitting the hay and consider switching your typical "nightcap" for warm tea.
As with most things in life: moderation is key.
*For more information on the effects of alcohol on sleep, we recommend checking out this PDF from Drinkaware: The Facts about Alcohol and Sleep.