A study in the journal Alcoholism: Clinical & Experimental Research suggests a before-bed nightcap may be a bad idea if you want to get a good night's sleep.
The participants in the study drank varying amounts of strong, weak or alcohol-free drinks about an hour and a half before going to bed. Those that consumed the most alcohol had the highest heart rate and got the least amount of REM sleep. This restless sleep pattern could lead to bouts of insomnia at night and extreme fatigue during the day.
If you drink every night before bed, you could find yourself in a vicious circle of pounding energy drinks to stay awake during the day and chugging beer at night to help you relax. Not exactly the best combination if want to live past 40. [Scientific American]