Sleeping and Dreaming
“Donnie, wake up! Class is starting,” exclaimed Hannah as she poked Donnie in his seat.
“How long have I been asleep?” asked Donnie drowsily.
“You’ve only been in class a few minutes,” replied Hannah.
“Wow, ‘cause it feels like I was asleep for the whole class. I think I just had a dream too.”
Overhearing the conversation, Mr. Baker asked the class “How many of you believe you seldom or never dream?”
Cindy raised her hand. “I never dream.”
In response, Mr. Baker explained, “It might surprise you to realize that you dream every night, and if you are getting adequate sleep, you should have around four to five dreams. During the first five to ten minutes, you often experience little ‘dreamlets.’
Confused, Cindy asked, “I don’t understand, Mr. Baker. How can I be dreaming? I don’t remember dreaming at all when I wake up.”
“There are timing mechanisms like a clock, inside all species,” continued Mr. Baker. "This clock is called a circadian rhythm, and it controls body temperature, blood pressure, and hormone levels. It can also affect periods of wakefulness and inactivity. Sleep is one of a variety of these biological rhythms.”
The Sleep Cycle
Sleep does not occur linearly, but rather as a cycle. Each phase of sleep has distinct characteristics. Take a moment to explore the sleep cycle and impacts it has on you and your brain. Click the player to begin.
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| Summary of Sleep Cycle | |
| Stage One |
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| Stage Two |
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| Stage Three |
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| Stage Four |
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| Stage Three Repeated |
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| Stage Two Repeated |
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| Rapid Eye Movement (REM) |
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The Importance of Sleep
Sleep allows the body to renew cells and maintain immunity. Research also has found that memories of the day become consolidated and filed during sleep. If someone does not get adequate sleep one night, the brain makes up for the loss by increasing the amount of REM sleep during the next night. Making up for deprived REM is called REM rebound.
How much sleep do you need? The average number of sleep hours needed varies according to age. Infants spend the majority of their sleep in REM. Conversely, teens need a great deal of sleep, but often do not get a sufficient amount. Sleep deprivation is common among today’s teens. Research conducted over the last fifteen years reveals that adolescents experience a unique shift in their circadian rhythm. Research further indicates that this age group often does not get drowsy until around 11:00 p.m. Given that adolescents need nine hours of sleep, their bodies want to wake up at 8:00 a.m. These findings prompted school systems across the country to change the start time of school.
The below chart indicates the number of hours the National Institutes of Health suggest someone gets at each phase of their life. This data was updated by the NIH in 2012.
| Age | Suggested Amount of Sleep |
| Newborns | 16-18 hours a day |
| Preschool-aged children | 11-12 hours a day |
| School-aged children | At least 10 hours a day |
| Teens | 9-10 hours a day |
| Adults (including elderly) | 7-8 hours a day |
Sleep Deprivation
Impacts of sleep deprivation are serious. A lack of sleep works much like debt from a credit card. Debt does not disappear, but must be paid off. The same proves true of sleep debt. The larger the debt, the more severe the symptoms become. Many causes of sleep deprivation exist. Take a moment to learn about various sleep disorders. Click the player to begin.
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Why We Dream?
Although research has not discovered a conclusive answer to the question, Why do we dream?, several theories exist that help explain possibilities. Take a moment to explore dream theories and determine which ones make most sense to you. Click the player to begin.
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Sleeping and Dreaming Review
Now that you have learned a bit about sleeping and dreaming, review your knowledge in this non-graded activity. Click the player to get started.