Why do some wines keep me awake at night?

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
Why do some wines keep me awake at night?
—Leah, Asheville, N.C.
Dear Leah,
Alcohol can interfere with how you sleep, disrupting REM sleep and exacerbating sleep disorders. It should never be used as a sleep aid. Avoid drinking wine right before bed, and at least a few hours before that if possible. And of course talk to your physician before consuming wine while taking any medications.
Many people find wine, which also contains a small amount of melatonin, to have a sedative effect, but your experience of wine keeping you awake at night is not uncommon either. Wine can actually exacerbate sleep apnea and insomnia, and it can also have multiple side effects that may interrupt your ability to fall asleep, including ringing in the ears, flushing and dehydration.
—Dr. Vinny