Study Is Intended to Be a Wake-Up Call

DECORAH, Iowa —  You’re in a strange place, there’s no alarm clock and it’s important to wake up early.

Do you stay up all night? Luther College Prof. Bill Moorcroft said many people have discovered a better way--the brain’s own alarm.

“Not everybody can do it. There are some who need three alarm clocks and a bucket of ice to get up. But many people really can do it on their own,” Moorcroft said.

That’s one view.

Critics say it’s poppycock.

“This is an old wives’ tale. People have studied this since the 1920s,” said Harold Zepelin, professor of psychology at Oakland University in Rochester, Mich.

“They say they can wake up any time they want, but what it comes down to is, all the evidence comes from their own reports,” Zepelin said. “You don’t have any objective statistics.”

Some people, he said, might be able to wake up if they have a regular sleep pattern and if their intended wake-up time corresponds with the cycles of rapid eye movement sleep. REM occurs every 80 to 100 minutes.

“I had one guy who said he could wake up within five minutes of his designated time. So I asked him to change the time, and he was an hour and a half long,” Zepelin said.

Such has been the debate for years.

Greg Mader, an official for the American Sleep Disorder Assn. in Rochester, Minn., said the topic has been batted back and forth in the group’s periodical Sleep.

But Moorcroft says he has new ammunition.

“The problem with other surveys is, you ask people the results but you’re never sure they tell the truth,” he said.

So he devised an experiment to take the self-reporting away.

Moorcroft recruited 15 volunteers, ages 19 through 62, who claimed they had an internal alarm. Each was asked to set a time to wake up without any external alarms. Each was given three tries, thus providing 45 tests, and some varied the wake-up time at least once.

In a departure from other tests, each participant wore a wrist sensor called an actigraph, which records movement every minute. The data produced by the sensor showed exactly when the subject woke up. There were 44 usable sets of data; the actigraph malfunctioned on the remaining test.

Of those 44 nights, 18 of the subjects awoke 15 minutes or less before the stated time. Another 10 were late by no more than 15 minutes.

“Fifteen minutes is pretty stringent criteria, given that you’re sleeping six, seven, maybe eight hours. I think that’s pretty good. If you give them a 30-minute window, you get another seven. That makes 80% within a half-hour of the target,” Moorcroft said.

“The interesting thing, and we didn’t expect this, is that the ones who had one or more different times were more successful than those who had the same time. I have no idea why. It’s counterintuitive,” he said.

The results would be even more impressive, he said, if it hadn’t been for one volunteer who missed all of his times. “There was one guy who was not very good. He woke up, but he was never close to the target,” he said.

Moorcroft said the results show that the brain can sometimes do things better during sleep than when the person is awake.

“The equivalent would be to put people in a room with no clocks or clues about time and tell them to signal when seven hours had gone by. I don’t think most people could do it,” he said. “But they can do it if they’re sleeping.”

Moorcroft said it wouldn’t surprise him that humans evolved with an internal alarm.

“Think about it. Alarm clocks are a fairly recent invention. Going back to caveman times, if you’re sleeping in a vulnerable place, you want to get out of there before dawn. Those humans would have survived and passed on the genes of this trait.”