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Adolescents and Sleep A summary of what researchers know about teenagers' need for sleep and why sleep affects memory and learning by FRONTLINE producer Sarah Spinks.
In making "Inside the Teenage Brain," we seemed to hit a nerve -- a parental one -- when we began looking into the world of teenagers and how they sleep. The patterns that young teens seemed to be experiencing -- an inability to go to sleep at night, followed by profound drowsiness on waking -- seemed so pervasive that it should come as no a surprise that what parents were seeing at home had already been corroborated in university sleep labs at Stanford and Brown.
Reseachers had always believed that sleep was governed by what was called the sleep-wake homeostasis, that is: "All other things being equal, ... the longer one is awake, the greater the pressure for sleep to occur. ... This process accounts for the increased need for sleep after staying awake all night." [1] It seemed perfectly reasonable that people would want to sleep when they were very tired. But it didn't account for a number of patterns that were obvious outside the lab: jet travellers woke up at 2 a.m. despite being exhausted after flying from Boston to London, teenagers had trouble falling asleep though they also seemed to be very tired, older people often woke up very early in the morning.
The Biological Clock
What researchers discovered is an internal biological clock, a clock that sometimes acts against the sleep-wake cycle by keeping us alert when we should be feeling tired. Sleep researchers Mary Carskadon, now at Brown University, and Bill Dement at Stanford had seen this biological clock in action when they tested a group of 10-12 year olds at Stanford. Dement, who pioneered sleep research at Stanford, wrote about these experiments: "After centuries of assuming the longer we are awake, the sleepier we will become and the more we will tend to fall asleep, we were confronted by the surprising result that after 12 hours of being awake, the subjects were less sleepy than they had been earlier in the same day, and at the 10 o'clock test, after more than 14 hours of wakefulness had elapsed ...they were even less sleepy." [2]
The researchers found that the biological clock opposed the sleep-wakefulness cycle at certain points of the day and at certain ages. It kept people awake when they were very tired. Just before puberty, that internal clock helped teens stay alert at night when they should have been falling asleep. The researchers called this a "phase-delay."
The biological clock or circadian rhythms (from the Latin words "circa" and "dies," or "around day") of smaller children don't show the same delays. Nothing is opposing their need to sleep in the evening. Until the age of 10, many children wake up fresh and energetic to start the day. In contrast, the biological clock of pre-teens shifts forward, creating a "forbidden" zone for sleep around 9 or 10 p.m. It is propping them up just as they should be feeling sleepy. Later on, in middle-age, the clock appears to shift back, making it hard for parents to stay awake just when their teens are at their most alert.
Carskadon discovered other important patterns in adolescent sleep. By studying alertness, she determined that teens, far from needing less sleep, actually needed as much or more sleep than they had gotten as children -- nine and a quarter hours. Most teenagers weren't getting nearly enough -- an hour and a half less sleep than they needed to be alert. And the drowsiness wasn't only in the early morning. Teens had a kind of sleep trough in the mid-afternoon and then perked up at night, even though they hadn't had a nap.
Carskadon is now exploring the effect of light in setting adolescent sleep patterns, for darkness seems to trigger the release of melatonin, often called the "sleep" hormone. Measuring melatonin also helps researchers define the different circadian rhythms of children, teens, and adults.
Sleep Debt
A great concern of sleep researchers is that teens are so sleep-deprived. Bill Dement speaks about the huge sleep debt that many teens and adults carry around with them every day. With most high schools in the U.S. starting around 7:20 a.m. and with many teens going to bed between 11 and 12 p.m., sleep researchers worry that teenagers are suffering an epidemic that is largely hidden. Since students are often driving to school, to sporting events, and home from late-night parties, this sleep debt holds huge risks. Many high school students know of someone, often a high-achieving kid, who on the drive back from a sporting event or dance simply fell asleep at the wheel. On a less dramatic note, there are literally millions of adolescents who feel despondent, get poor marks, or are too tired to join high-school teams all because they are getting too little sleep. Because of their deep concern about these issues, sleep researchers are pushing for later school start times and are trying to introduce sleep issues into the high school curriculum.
Sleep, Learning, and Memory
The other area of sleep research relevant to teenagers, their parents, and teachers is the effect of sleep on learning and memory. In experiments done at Harvard Medical School and Trent University in Canada, students go through a battery of tests and then sleep various lengths of time to determine how sleep affects learning. What these tests show is that the brain consolidates and practices what is learned during the day after the students (or adults, for that matter) go to sleep. Parents always intuitively knew that sleep helped learning, but few knew that learning actually continues to take place while a person is asleep. That means sleep after a lesson is learned is as important as getting a good night's rest before a test or exam.
This research is done by giving students a series of tests. The students are trained, for instance, to catch a ball attached by a string to a cone-like cup. As they repeat the skill during the test day, they are able do it faster and more accurately. Let's say they go from catching a ball 50 percent to 70 percent of the time over a period of half an hour. The students who get a good night's sleep improve when they are retested. On a retest three days after they have a good night's sleep, they might catch a ball 85 percent of the time. The other students who got less than six hours sleep either do not improve or actually fall behind.
Some of the tests are more demanding. They are called cognitive procedural tasks and they mimic what a student might learn in physics or math, or in certain sports. They present the student with something new to be learned or require an ability to conceptualize, to form a picture of the task in their minds.
Source: PBS
It's the mystery of mysteries -- especially to parents -- the unpredictable and sometimes incomprehensible moods and behaviors of the American teenager. Generations of adults have pondered its cause. Hormones? Rock music? Boredom? Drugs?
In "Inside the Teenage Brain," FRONTLINE chronicles how scientists are exploring the recesses of the brain and finding some new explanations for why adolescents behave the way they do. These discoveries could change the way we parent, teach, or perhaps even understand our teenagers. New neuroscience research has shown that a crucial part of the brain undergoes extensive changes during puberty -- precisely the time when the raging hormones often blamed for teen behavior begin to wreak havoc. It's long been known that the architecture of the brain is largely set in place during the first few years of life. But with the aid of new technologies such as magnetic resonance imaging (MRI), scientists are mapping changes in pre-teen and teenage brains and finding evidence that remarkable growth and change continue for decades.
The vast majority of brain development occurs in two basic stages: growth spurts and pruning. In utero and throughout the first several months of life, the human brain grows at a rapid and dramatic pace, producing millions of brain cells.
"This is a process that we knew happened in the womb, maybe even in the first 18 months of life," explains neuroscientist Dr. Jay Giedd at the National Institute of Mental Health. "But it was only when we started following the same children by scanning their brains at two-year intervals that we detected a second wave of overproduction."
This second wave -- occurring roughly between ages 10 and 13 -- is quickly followed by a process in which the brain prunes and organizes its neural pathways. "In many ways, it's the most tumultuous time of brain development since coming out of the womb," says Giedd.
Confronted by these new discoveries, academics, counselors, and scientists are divided on just what all this means for children.
"Our leading hypothesis ... is the 'use it or lose it' principle," Jay Giedd tells FRONTLINE. "If a teen is doing music or sports or academics, those are the cells and connections that will be hardwired. If they're lying on the couch or playing video games or [watching] MTV, those are the cells and connections that are going to survive."
But others voice caution in leaping to conclusions about the implications of these findings.
"The relationship between desired behaviors and brain structure is totally unknown," John Bruer tells FRONTLINE. He is president of the James S. McDonnell Foundation and author of The Myth of the First Three Years. "This simple, popular, newsweekly-magazine idea that adolescents are difficult because their frontal lobes aren't mature is one we should be very cautious of."
This FRONTLINE report also looks at research that is helping scientists understand another puzzling aspect of adolescent behavior -- sleep.
Mary Carskadon, director of the E.P. Bradley Hospital Sleep Research Laboratory at Brown University, has spent years mapping the brains of sleepy teens. She has calculated that most teens get about seven and a half hours of sleep each night, while they need more than nine. Some say these sleep debts can have a powerful effect on a teen's ability to learn and retain new material -- especially abstract concepts like physics, math, and calculus.
Despite all the new scientific research, "Inside the Teenage Brain" suggests that there is a consensus among experts that the most beneficial thing for teenagers is good relationships with their parents. Even Dr. Giedd wonders about the kinds of lessons parents can draw from his science. "The more technical and more advanced the science becomes, often the more it leads us back to some very basic tenets. ... With all the science and with all the advances, the best advice we can give is things that our grandmother could have told us generations ago: to spend loving, quality time with our children."
Ellen Galinsky, a social scientist and the president of the Families and Work Institute, has seen scientific fads come and go. But she says her research for a book about children shows there are enduring lessons for parents. Drawing on her interviews with more than a thousand children, she found that, to her surprise, teens were yearning for more time and more communication with their parents, even when they seemed to be pushing them away. She told FRONTLINE, "Even though the public perception is about building bigger and better brains, what the research shows is that it's the relationships, it's the connections, it's the people in children's lives who make the biggest difference."
Source: PBS
Video Description
Adolescents and Sleep A summary of what researchers know about teenagers' need for sleep and why sleep affects memory and learning by FRONTLINE producer Sarah Spinks.
In making "Inside the Teenage Brain," we seemed to hit a nerve -- a parental one -- when we began looking into the world of teenagers and how they sleep. The patterns that young teens seemed to be experiencing -- an inability to go to sleep at night, followed by profound drowsiness on waking -- seemed so pervasive that it should come as no a surprise that what parents were seeing at home had already been corroborated in university sleep labs at Stanford and Brown.
Reseachers had always believed that sleep was governed by what was called the sleep-wake homeostasis, that is: "All other things being equal, ... the longer one is awake, the greater the pressure for sleep to occur. ... This process accounts for the increased need for sleep after staying awake all night." [1] It seemed perfectly reasonable that people would want to sleep when they were very tired. But it didn't account for a number of patterns that were obvious outside the lab: jet travellers woke up at 2 a.m. despite being exhausted after flying from Boston to London, teenagers had trouble falling asleep though they also seemed to be very tired, older people often woke up very early in the morning.
The Biological Clock
What researchers discovered is an internal biological clock, a clock that sometimes acts against the sleep-wake cycle by keeping us alert when we should be feeling tired. Sleep researchers Mary Carskadon, now at Brown University, and Bill Dement at Stanford had seen this biological clock in action when they tested a group of 10-12 year olds at Stanford. Dement, who pioneered sleep research at Stanford, wrote about these experiments: "After centuries of assuming the longer we are awake, the sleepier we will become and the more we will tend to fall asleep, we were confronted by the surprising result that after 12 hours of being awake, the subjects were less sleepy than they had been earlier in the same day, and at the 10 o'clock test, after more than 14 hours of wakefulness had elapsed ...they were even less sleepy." [2]
The researchers found that the biological clock opposed the sleep-wakefulness cycle at certain points of the day and at certain ages. It kept people awake when they were very tired. Just before puberty, that internal clock helped teens stay alert at night when they should have been falling asleep. The researchers called this a "phase-delay."
The biological clock or circadian rhythms (from the Latin words "circa" and "dies," or "around day") of smaller children don't show the same delays. Nothing is opposing their need to sleep in the evening. Until the age of 10, many children wake up fresh and energetic to start the day. In contrast, the biological clock of pre-teens shifts forward, creating a "forbidden" zone for sleep around 9 or 10 p.m. It is propping them up just as they should be feeling sleepy. Later on, in middle-age, the clock appears to shift back, making it hard for parents to stay awake just when their teens are at their most alert.
Carskadon discovered other important patterns in adolescent sleep. By studying alertness, she determined that teens, far from needing less sleep, actually needed as much or more sleep than they had gotten as children -- nine and a quarter hours. Most teenagers weren't getting nearly enough -- an hour and a half less sleep than they needed to be alert. And the drowsiness wasn't only in the early morning. Teens had a kind of sleep trough in the mid-afternoon and then perked up at night, even though they hadn't had a nap.
Carskadon is now exploring the effect of light in setting adolescent sleep patterns, for darkness seems to trigger the release of melatonin, often called the "sleep" hormone. Measuring melatonin also helps researchers define the different circadian rhythms of children, teens, and adults.
Sleep Debt
A great concern of sleep researchers is that teens are so sleep-deprived. Bill Dement speaks about the huge sleep debt that many teens and adults carry around with them every day. With most high schools in the U.S. starting around 7:20 a.m. and with many teens going to bed between 11 and 12 p.m., sleep researchers worry that teenagers are suffering an epidemic that is largely hidden. Since students are often driving to school, to sporting events, and home from late-night parties, this sleep debt holds huge risks. Many high school students know of someone, often a high-achieving kid, who on the drive back from a sporting event or dance simply fell asleep at the wheel. On a less dramatic note, there are literally millions of adolescents who feel despondent, get poor marks, or are too tired to join high-school teams all because they are getting too little sleep. Because of their deep concern about these issues, sleep researchers are pushing for later school start times and are trying to introduce sleep issues into the high school curriculum.
Sleep, Learning, and Memory
The other area of sleep research relevant to teenagers, their parents, and teachers is the effect of sleep on learning and memory. In experiments done at Harvard Medical School and Trent University in Canada, students go through a battery of tests and then sleep various lengths of time to determine how sleep affects learning. What these tests show is that the brain consolidates and practices what is learned during the day after the students (or adults, for that matter) go to sleep. Parents always intuitively knew that sleep helped learning, but few knew that learning actually continues to take place while a person is asleep. That means sleep after a lesson is learned is as important as getting a good night's rest before a test or exam.
This research is done by giving students a series of tests. The students are trained, for instance, to catch a ball attached by a string to a cone-like cup. As they repeat the skill during the test day, they are able do it faster and more accurately. Let's say they go from catching a ball 50 percent to 70 percent of the time over a period of half an hour. The students who get a good night's sleep improve when they are retested. On a retest three days after they have a good night's sleep, they might catch a ball 85 percent of the time. The other students who got less than six hours sleep either do not improve or actually fall behind.
Some of the tests are more demanding. They are called cognitive procedural tasks and they mimic what a student might learn in physics or math, or in certain sports. They present the student with something new to be learned or require an ability to conceptualize, to form a picture of the task in their minds.
Source: PBS
Documentary Description
It's the mystery of mysteries -- especially to parents -- the unpredictable and sometimes incomprehensible moods and behaviors of the American teenager. Generations of adults have pondered its cause. Hormones? Rock music? Boredom? Drugs?
In "Inside the Teenage Brain," FRONTLINE chronicles how scientists are exploring the recesses of the brain and finding some new explanations for why adolescents behave the way they do. These discoveries could change the way we parent, teach, or perhaps even understand our teenagers. New neuroscience research has shown that a crucial part of the brain undergoes extensive changes during puberty -- precisely the time when the raging hormones often blamed for teen behavior begin to wreak havoc. It's long been known that the architecture of the brain is largely set in place during the first few years of life. But with the aid of new technologies such as magnetic resonance imaging (MRI), scientists are mapping changes in pre-teen and teenage brains and finding evidence that remarkable growth and change continue for decades.
The vast majority of brain development occurs in two basic stages: growth spurts and pruning. In utero and throughout the first several months of life, the human brain grows at a rapid and dramatic pace, producing millions of brain cells.
"This is a process that we knew happened in the womb, maybe even in the first 18 months of life," explains neuroscientist Dr. Jay Giedd at the National Institute of Mental Health. "But it was only when we started following the same children by scanning their brains at two-year intervals that we detected a second wave of overproduction."
This second wave -- occurring roughly between ages 10 and 13 -- is quickly followed by a process in which the brain prunes and organizes its neural pathways. "In many ways, it's the most tumultuous time of brain development since coming out of the womb," says Giedd.
Confronted by these new discoveries, academics, counselors, and scientists are divided on just what all this means for children.
"Our leading hypothesis ... is the 'use it or lose it' principle," Jay Giedd tells FRONTLINE. "If a teen is doing music or sports or academics, those are the cells and connections that will be hardwired. If they're lying on the couch or playing video games or [watching] MTV, those are the cells and connections that are going to survive."
But others voice caution in leaping to conclusions about the implications of these findings.
"The relationship between desired behaviors and brain structure is totally unknown," John Bruer tells FRONTLINE. He is president of the James S. McDonnell Foundation and author of The Myth of the First Three Years. "This simple, popular, newsweekly-magazine idea that adolescents are difficult because their frontal lobes aren't mature is one we should be very cautious of."
This FRONTLINE report also looks at research that is helping scientists understand another puzzling aspect of adolescent behavior -- sleep.
Mary Carskadon, director of the E.P. Bradley Hospital Sleep Research Laboratory at Brown University, has spent years mapping the brains of sleepy teens. She has calculated that most teens get about seven and a half hours of sleep each night, while they need more than nine. Some say these sleep debts can have a powerful effect on a teen's ability to learn and retain new material -- especially abstract concepts like physics, math, and calculus.
Despite all the new scientific research, "Inside the Teenage Brain" suggests that there is a consensus among experts that the most beneficial thing for teenagers is good relationships with their parents. Even Dr. Giedd wonders about the kinds of lessons parents can draw from his science. "The more technical and more advanced the science becomes, often the more it leads us back to some very basic tenets. ... With all the science and with all the advances, the best advice we can give is things that our grandmother could have told us generations ago: to spend loving, quality time with our children."
Ellen Galinsky, a social scientist and the president of the Families and Work Institute, has seen scientific fads come and go. But she says her research for a book about children shows there are enduring lessons for parents. Drawing on her interviews with more than a thousand children, she found that, to her surprise, teens were yearning for more time and more communication with their parents, even when they seemed to be pushing them away. She told FRONTLINE, "Even though the public perception is about building bigger and better brains, what the research shows is that it's the relationships, it's the connections, it's the people in children's lives who make the biggest difference."
Source: PBS
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