Why do we need sleep? Introduction to Psychology Why do we sleep and dream?
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Focus Questions • Why do we need sleep, anyway? • What happens if we get too little sleep?
The purpose of sleep… Sleep serves many purposes. Sleep • protects • rejuvenates and restores • makes memories • conserves energy • feeds creativity • plays a key role in brain development • plays a role in growth • cleans out the brain
Sleep Protects • Sleep may be an adaptation that helped organisms survive. Examples: Grazing animals – sleep less ex. giraffes 2 hours/day horses 3-4 hours/day cats – 14 hours/day bats/chipmunks – 20 hours/day
Restores & Rejuvenates Sleep provides an opportunity for the body to repair itself. -major restorative functions of the body like muscle growth & tissue repair occur mostly at night Sleep deprivation over period of time leads to decreased functioning of immune system.
Makes memories Sleep restores and rebuilds our memories of the day’s experiences.
Conserves energy Sleep helps us conserve our energy resources.
Feeds creativity Sleep feeds creative thinking. Boosts our ability to think, learn, & problem solve Increases our ability to make connections
May play a role in growth During sleep, the pituitary gland releases a growth hormone. As we age, we release less of this hormone & spend less time in deep sleep.
May play a role in brain development Sleep plays a critical role in brain development of infants and children. Spend 13 to 14 hours/day (more than ½ in REM) Brain plasticity (changes in the structure & organization of the brain) is connected to sleep. in adults – link between sleep deprivation & ability to learn/perform tasks
What happens if we don’t get enough sleep? • Academic Functioning Decreases • Difficulty studying, reduced productivity • Lower alertness & concentration • Impairs judgment; more difficult to make decisions • Impairs memory • Weight Gain • sleep deprivation increases ghrelin (hunger arousing hormone) & decreases leptin (hunger suppressing hormone) • sleep deprivation increases cortisol (stress hormone) – stimulates body to produce fat • Children & adults who sleep less are fatter than those who sleep more
3. Immune System Functioning • Sleep deprivation suppresses immune cells that fight off infections & cancer • People who sleep 7-8 hours/night outlive sleep deprived people 4. Decreased Reaction Time • Biggest danger • Driving/Work that requires fast responses • 20% of all crashes (1 million) due to driver fatigue (NHTSA) • 1/3 of all Americans report nodding off while driving
5. Mood Changes • Irritability, less tolerant, loss of sense of humor • Puts in at greater risk for depression • People with insomnia 10x more likely to be depression; 17x more likely to have anxiety as well (Univ of Texas study 2005)
Why do we need sleep? • https://www.youtube.com/watch?v=pwNMvUXTgDY