Trouble falling asleep? Some may (unwisely) suggest that a nightcap might help you fall asleep more quickly. But how does this impact the actual quality of sleep?
I am on a personal quest to improve my sleep, and I’ve measured my sleep while testing a bunch of home remedies and sleep products. This time, I’m putting the nightcap to the test.
I measured my sleep quality after having two beers before bed to see how it would impact my deep sleep and REM (Rapid Eye Movement) sleep stages. Unfortunately, even though drinking a nightcap helped me fall asleep more quickly, I ended up awake for a large portion of the night. I also had worse deep sleep and REM sleep compared to a normal night. I would definitely recommend against drinking if you’re in search of better sleep.
Methodology
Using an Apple Watch, I measured my sleep quality for one normal night and one night after drinking two beers. I usually don’t drink alcohol, so the impact of two beers is pretty significant for me. I kept my caffeine intake and activity levels consistent across both days. I started my bedtime wind-down at midnight and entered bed between 12:30am and 1am each night. I woke up with my alarm at 8:30am every morning.
Sleep quality is measured based on the amount of sleep in each sleep stage. Time in REM and deep sleep contributes to a higher sleep score while time awake lowers the sleep score. The full details behind the sleep score can be found here.
Results
Normal Sleep (Control)
Sleep with a Nightcap (2 Beers)
| Trial | Awake (Mins) | REM (Mins) | Core (Mins) | Deep (Mins) |
|---|---|---|---|---|
| Control | 30 | 95 | 289 | 52 |
| Nightcap | 135 | 71 | 225 | 38 |
My sleep score dropped to -26 compared to a normal night’s sleep score of 117. Sleep deteriorated across all categories with more time awake, less time in REM and less time in deep sleep.
Discussion
Even though I was able to fall sleep quickly after the nightcap, I woke up in the middle of the night. My sleep felt restless. Between 2:30am and 5am, I drifted in and out of consciousness, and I felt slightly hungover.
When I did finally fall back asleep, I didn’t get the REM sleep I needed to recover mentally the next day. I normally avoid alcohol on a day-to-day basis, and I don’t see any reason to change that habit considering how it affects my sleep negatively. If you try this out yourself, please drink responsibly.
David Stewart
David is a former statistics consultant.