We spend about one third of our life sleeping!
Why do we sleep? No one really
• Inactivity theory: Moving around at night is
• Saving energy theory: Moving around uses
energy, so we don’t need to eat as much if we
• Body repair theory: The body repairs itself when
• Brain plasticity theory: The brain is very
complicated, and may need sleep to help it stay
How long should you sleep every
• We should sleep between 7 and 9 hours every
The sleep cycle
REM sleep is
the best for
Sea otters hold hands when they sleep
so they don’t separate.
• What percent of our life do we spend
• What are some things that can help us sleep?
• What is a bad dream called?
• When do we get “jet lag”?
• What is it called when we can’t sleep?
• How long should we sleep every night?
• What is it called when we sleep for a short
time to get refreshed?
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