Humans have an elegant and intricate system of internal processes that help our bodies keep track of time while also playing a role in everything from sun exposure to caffeine to meal timing. Doesn’t explain “precise awakening”.
Sarah Mosquera/NPR
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Sarah Mosquera/NPR
Humans have an elegant and intricate system of internal processes that help our bodies keep track of time while also playing a role in everything from sun exposure to caffeine to meal timing. Doesn’t explain “precise awakening”.
Sarah Mosquera/NPR
Maybe this happens to you too sometimes:
You go to bed with morning obligations on your mind, such as catching a flight or an important meeting. The next morning, you wake yourself up to find yourself just a minute or two behind your alarm clock.
what’s going on Is it pure luck? Or do you have an uncanny ability to wake up exactly on time without help?
I know many people are coming Dr. Robert Stickgold I have wondered about this phenomenon for years.
Stickgold, a cognitive neuroscientist at Harvard Medical School and Beth Israel Deaconess Medical Center, said, “This is one of the questions in sleep research, and everyone in the field knows it’s clearly true. They seem to agree that there is no way.
Stickgold even remembers taking this issue to a mentor when he was just starting out in the field. “I can assure you that we sleep researchers are all saying, ‘This is ridiculous, it’s impossible,'” he says.
Still, I believe Stickgold is still there teeth What about that? “This kind of precise awakening has been reported by hundreds and thousands of people,” he says. “I can get up at 7:59 and turn off the alarm clock before my wife wakes up.”
Of course, it is well known that the human body has a sophisticated and complex system of internal processes. Shaped in part by exposure to sunlight, caffeine, diet, exercise, and other factors, these processes regulate circadian rhythms throughout the approximately 24-hour day and night cycle, affecting when we go to bed and when we wake up. give.
If you’re getting enough sleep and your lifestyle aligns with your circadian rhythm, you should usually wake up at about the same time each morning, adjusting for seasonal differences. Philip GehrmannSleep scientist at the University of Pennsylvania.
But it doesn’t fully explain this phenomenon of waking up exactly minutes before your alarm, especially at times outside your normal schedule.
“I hear this all the time,” he says. “I think part of the reason is the fear of being late.”
Scientists are curious — mixed results
In fact, several scientists have investigated this mystery over the years, with certainly mixed results.
For example, a small 15 study Starting in 1979, we found that over two nights, subjects were able to wake up within 20 minutes of their goal more than half the time. He followed her best two subjects for another week, but the accuracy soon plummeted.another small experiment When participants were asked to choose when to wake up, it was concluded that about half of spontaneous awakenings occurred within 7 minutes of the choices written down before going to bed.
Other researchers took a more subjective approach and asked people to report their ability to wake up at a specific time. replied that they could do this. In fact, Stickgold says it’s quite possible that “like many things we think we do all the time, we only do them occasionally.”
OK, the scientific evidence isn’t exactly overwhelming.
But there was one interesting piece of evidence that caught my eye. Dr. Phyllis Geedirector of sleep medicine at Northwestern University Feinberg School of Medicine.
Stress hormones may play a role
In the late 1990s, a group of German researchers wanted to understand how the anticipation of waking up affected a phenomenon known as sleep. HPA axis – A complex system in the body that deals with our response to stress and includes the hypothalamus, pituitary gland, and adrenal glands.
Jan BourneOne of the study’s authors says he knew the levels of hormones stored in the pituitary gland. actionbegins to increase before the hour you habitually wake up, which signals the adrenal glands to release cortisol, the so-called “stress hormone” that helps wake you up among other things.
“In this context, we decided to give it a try, and it actually worked as hypothesized,” says Born, now a professor of behavioral neuroscience at the University of Tübingen in Germany.
Here’s what Bourne and his team did. They found 15 of them, who usually wake up around 7 or 7:30 a.m., put them in a sleep lab, and took blood samples over three nights.
Subjects were divided into three different groups. Others were assigned at 9am. A third group was given a wake-up time of 9:00 AM, but woke up unexpectedly at 6:00 AM.
Bourne says there was a noticeable difference as the wake-up time approached.
Subjects who expected to wake up at 6:00 a.m. had significantly elevated levels of ACTH starting at about 5:00 a.m. It was as if their bodies knew they had to get up early, Vaughn says.
“This is an excellent adaptive readiness response of the organism,” Bourne says with a laugh.
The same rise in stress hormones before waking was not recorded in members of the group who did not plan to wake up early, but were surprised by the 6:00 a.m. wake-up call. In the rising group, there was no significant increase in ACTH one hour before waking (which, according to Born, suggests that the morning was simply too late to see the same effect).
Born’s experiment didn’t really measure whether people would eventually wake up on their own before a predetermined time, but he said the findings raise some interesting questions about the phenomenon. After all, how did their bodies know they had to get up earlier than normal?
“It shows that the system is plastic and can itself adapt to changes in time,” he says. It also suggests some ability to utilize this “system” while awake. The idea is not at all foreign to the field of sleep research, he says.
The unsolved mysteries of science
“It’s well known that there are certain mechanisms in the brain that allow you to voluntarily influence your body and brain during sleep,” Born says. It points to research that shows it can help you sleep more deeply.
Northwestern’s Zee says there are likely “multiple biological systems” that could explain why some people are able to wake up at certain times without an alarm clock. Anxiety about waking up can somehow “disable” our main body clock, she says.
“This paper is really great because it shows that your brain is still working,” she says.
Of course, exactly how it works and how much we can trust this enigmatic internal alarm system remains a big open question. It wasn’t meant to be scrapped, but Harvard’s Stickgold says he’s not ready to dismiss the question.
“It’s a true scientific mystery,” he says. And, as in many fields, when faced with a mystery, “it’s arrogant to assume that it can’t happen when you don’t know how it will happen,” he added.
This story is part of NPR’s regular science series Finding Time—A Fourth Dimensional Journey to Finding Out What Drives Us.
