Body can sleep later than brain

FORT WORTH, Texas - Imagine waking up in the night and being unable to move.

So you lie there for what seems like hours, trying to wiggle your fingers or toes, but you are paralyzed. You want to call out for help, but you can’t draw a deep enough breath to make a loud sound.

Eventually, you’re able to move a little, and then your whole body begins to respond.

Scary, huh?

Weird, too. But it happens to people all the time.

It’s called sleep paralysis, and it typically occurs at the very beginning or end of sleep. The experience lasts a few minutes at the most, and there’s no harm done, aside from fright.

“It’s terrifying the first time it happens,” said Dr. Barbara Phillips, director of the Samaritan Sleep Center and chairwoman of the board of the National Sleep Foundation.

Phillips explained in an e-mail that sleep paralysis happens as the body is coming out of REM, or rapid-eye-movement, sleep.

“During non-REM sleep, our brains are ‘turned off’ but our bodies can be active,” she said. This is when people experience sleep disturbances such as tooth-grinding or sleepwalking.

“In contrast, our brains are very active (probably as active as when we are awake) during REM sleep, but we are actually paralyzed,” she said. Researchers think that’s what keeps us from acting out our dreams.

“With sleep paralysis, the paralysis that is normal during REM sleep intrudes into the waking state,” she said.

Kathryn Hansen, director of the St. Joseph Hospital Sleep Wellness Center, put it this way: “The brain wakes up before the body wakes up.”

Sometimes, sleep paralysis is accompanied by hypnagogic hallucinations, or “waking dreams,” Phillips said.

In many such cases, people think they see a dark or menacing figure in the room, or they hear a strange sound but can’t pinpoint the source. Some researchers have hypothesized that people who report alien abductions are experiencing sleep paralysis in conjunction with such a hallucination.

People are more likely to experience sleep paralysis, the experts said, if they are deprived of sleep, work odd shifts or have erratic sleep schedules. Hansen said it also can come with stress or anxiety.

People who are in withdrawal from alcohol or drugs that can suppress REM sleep, such as antidepressants, also can be predisposed to the experience.

The “classic example is the college kid who parties hard during spring break, and wakes up on the beach unable to move,” Phillips said. That person is deprived of sleep, on an odd schedule and has drunk to much — all the risk factors.

Hansen recommends the person “develop some good sleep habits,” such as decreasing caffeine intake, exercising and going to bed and rising at the same time each day.