By Richard Mariani
San Antonio Express-News
Confession time: On occasion, I imbibe more adult beverages than I should. I know this not from the pounding headaches I suffer the next morning, nor the embarrassing memories that arise from the haze the next day.
No, I know I’ve had too much to drink when it’s 3 a.m. and I’m awake and as alert as a prison guard and unable, no matter how many sheep I count, to fall back to sleep.
I’ve long suspected it’s the alcohol that causes this sleepus interruptus, but until I spoke with Mahesh Thakker I never knew why.
Booze, he explained, is bad for the snooze.
Thakker, associate professor and director of research at the University of Missouri School of Medicine’s department of neurology, and his team recently published a study explaining how alcohol interferes with your good night’s sleep.
You’re correct if you question the very premise that alcohol messes with sleep. After all, most people get sleepy when they drink. In fact, averaging results from a number of studies, about 20 percent of Americans rely on a quick nightcap (or two, or three) to help them nod off each evening. And that works … to a point.
The relationship between alcohol and sleep is complicated. First, alcohol suppresses what’s known as rapid eye movement, or REM, sleep. As the name suggests, during REM sleep your eyes move quickly in all directions. And most dreams occur during REM sleep. (It’s during non-REM sleep, by the way, that the body repairs and builds tissue and strengthens the immune system.)
“The suppression of REM sleep results in what’s known as ‘REM rebound,’ which can jolt you awake, usually four to five hours after you’ve first fallen asleep,” explained Thakker, who has been studying alcohol’s effects on sleep for more than five years.
But how does it do that? Sleep researchers previously thought that alcohol triggered sleepiness by changing circadian rhythm, often called the body’s 24-hour clock.
By studying animals, Thakker and his team instead discovered that alcohol shifts the body’s sleep homeostasis. This is the built-in mechanism that balances sleepiness and wakefulness. Basically, it means that the longer you’ve been awake, the more likely you are to feel sleepy, and the longer you’ve been asleep, the more likely you are to wake up. Simple, right?
But alcohol throws this balance out of whack.
Let’s say you normally go to sleep at 11 p.m. But if you start drinking at 7 in the evening, you shift your body’s sleep homeostasis forward by four hours. So instead of waking up alert and well-rested at 7 a.m., you wake up alert (though maybe not so well rested) – and watching “M*A*S*H” reruns – at 3 in the morning.
To add insult to injury, alcohol also acts as a diuretic, so it’ll also get you up and out of bed earlier in the morning to use the bathroom.
Alcohol takes an even more dramatic toll on problem drinkers. Alcoholics often suffer severe insomnia, and even when they try to quit, these sleep disturbances can continue for up to three years, said Thakker.
“So they’re groggy, fatigued, even depressed,” he explained. “This makes recovery that much more difficult and can even push them to relapse.”
Alcohol’s effects on sleep don’t necessarily mean you have to become a teetotaler. To avoid the worst consequences, stop drinking two to four hours before bedtime. This gives your body time to metabolize the alcohol and get it out of your system.
If keeping track of time is too difficult (you drinking, after all), Thakker offers this simple strategy: Stop drinking when you start to feel sleepy. That’s your body’s way of letting you know you’ve had enough and that if you continue drinking you’ll soon be enjoying the Korean War high jinks of Hawkeye, Hot Lips and Cpl. Radar O’Reilly.
Heed your body’s message.