Jim > > > I wake up at 2am if I've had two or more servings of alcohol after 6pm.  Like clockwork.

Mike > What time do you go to sleep and how long do you normally sleep? Can you explain why this happens to you from a metabolic perspective?

I go to bed about 10pm and usually wake around 6-6:30am.  I too was wondering why it happens.  Some facts that I found:

Even in small doses, alcohol can cause early sedation or sleepiness, awaking during the night, and suppression of REM (rapid eye movement) sleep. REM sleep is the dreaming stage of sleep, however, when REM sleep occurs near wakefulness, it can cause hallucinations.
{"Alcohol effects on the brain," Alcohol Research Center, LSUHSC - Lousiana State University Health Sciences Center, Aug. 2002} 

Alcohol taken in the evening or as a ‘nightcap’ is counter-productive. It helps you fall asleep, but hours later during the night, it has the opposite effect and keeps you awake.
{American Family Physician, 1995, in the Health Gazette, Mar. 1995} 

Fatigue due to alcohol consumption is common. A nightcap may get you to sleep, but drinking late at night produces troubled, fragmented sleep.
{Excedrin Headache Relief Update, 1996} 

Avoid alcohol before going to bed. A nightcap makes you drowsy at first, but when the alcohol leaves your system your blood sugar will drop, causing you to wake.
{"Older women," Natural Health magazine, Nov./Dec. 1999} 

Alcohol robs a person of ‘dreaming sleep,’ which is essential to well-being. The relaxing ‘nightcap’ can lead to sleeplessness and tiredness with irritability the next morning.
{"You are what you drink," Luks and Barbato, 1989} 

Consider not having a ‘nightcap’ as one of the sleep hygiene steps for better slumber. Alcohol may help some people fall asleep, but it interferes with substances in the brain that allow for continuous sleep. The result is repeated waking (or partial waking) through the night, leading to fewer hours of truly deep restful sleep. Avoid drinking alcohol between dinner and bedtime.
{"To eat, perchance to sleep," Washington Post Health, Aug. 29, 2000} 

Avoid an alcoholic nightcap within three hours of bedtime. Alcohol, which initially acts as a sedative, can also have a stimulant effect and will interfere with your sleep later in the night.
{"Living Better, Longer," Prevention, Sep. 2000} 

The use of alcohol disrupts both REM and slow wave sleep, both vital in the restoration and rebuilding of the mind and the body. Alcohol affects the neurotransmitters that regulate these two phases of sleep as well as the onset of sleep.
{"Alcohol and sleep, no thanks, I’m sleeping," sleepdisorders.about.com, Nov. 2004} 

Don't drink any alcohol within four to six hours of bedtime if you want a good night’s sleep.
{Justiniano F. Campa, MD, Neurology Dept. of University of Virginia Medical School} 

As a lifestyle change to make your sleep more restful, avoid alcohol in the late afternoon and evening.
{"Getting a good night’s sleep," Senior Advisor, Blue Cross, Blue Shield, 1998} 

How to get better sleep: don't sleep in late on weekends and don't drink alcohol after 6 p.m.
{ABC News, Jennifer Josephs, "Health and Living." April 3, 2000} 

To head off insomnia, practice good sleep habits: keep alcohol consumption to a minimum.
{"Falling asleep," Anne Moulton, MD, internist, McCall’s magazine, May 1997} 

One of the common causes of chronic insomnia is the use of alcohol.
{"You are getting sleepy ...," Consultation, Jay Siwek, MD, Washington Post Health, Feb. 15, 2000} 

Some people drink alcohol to help them drift off to sleep, but it isn't helpful over the long haul because alcohol disrupts the brainstem sleep mechanism, resulting in "rebound insomnia." If you use alcohol, you will probably awaken during the night because your body will need more "sedative."
{"Midlife insomnia," Dr. Christiane Northrup’s Health Wisdom for Women, July 2000} 

According to studies in ‘Alcohol Health Research World,’ 1995, a moderate dose of alcohol consumed as much as six hours before bedtime can increase wakefulness during the second half of sleep. By the time this effect occurs, the dose of alcohol consumed earlier has already been eliminated from the body, suggesting a relatively long-lasting change in the body’s mechanisms of sleep regulation.
{J Clin Psychopharmacol, 1996 and Addict Biol 1997}
{Alcohol Alert, CBSHealthWatch - Library, June 2000} 

Avoid alcohol, a depressant that induces sleep but disrupts sleep cycles during the night.
{"Insomnia," The Johns Hopkins Medical Letter, ‘Health after 50’} 

The use of alcohol makes getting up more difficult because it disrupts natural sleep, exerting a direct influence on the brain’s arousal apparatus. Even an innocent ‘nightcap’ can suppress the all-important dream stage of sleep, as well as delta sleep, which is physiologically the deepest stage of sleep. Alcohol acts as a diuretic, so the need to go to the bathroom at night disrupts sleep.
{"A good night’s sleep," Jerrold S. Maxmen, MD} 

Avoid alcohol four to five hours before bedtime. Although alcohol can make people drowsy, it actually distorts the normal brain-wave pattern of sleep and prompts more frequent awakenings, sometimes causing difficulty getting back to sleep.
{"Healing anxiety with herbs," Harold Bloomfield, MD, 1998} 

There are 40 million Americans who are troubled by insomnia. Avoid late afternoon or evening caffeine or alcohol.
{"What to take when you can't sleep," Bottom line Health newsletter, April 2001} 

Alcohol inhibits the release of melatonin, a hormone derived from serotonin, an antioxidant that is linked with decreasing toxicity and decreasing cancer.
{"Eat and beat cancer," J. Robert Hatherhill, PhD, 1998} 

Alcohol can disrupt your melatonin supply. The fact that drinking alcoholic beverages at night makes your sleep restless appears related in part to melatonin output.
{"Melatonin-boosting lifestyle," Natural Health magazine, 1999} 

Volunteers who drank the equivalent of one or two glasses of wine at 7 o'clock in the evening had 41% less melatonin at midnight, compared to the nights when they did not drink alcohol. This could be why alcohol disrupts sleep.
{Women’s Health Connection newsletter, Dec. 1995/Jan. 1996} 

Remember that any amount of alcohol use is a sure fire way to stop your body’s production of melatonin for that night.
{"Treat your colds naturally and avoid unnecessary over-the-counter drugs," Dr. Joseph Mercola, mercola.com, Oct. 2005}