ListWhat are 5 things that

you absolutely must do on a daily basis?

Consider thisThe average teenager in America will spend 65

days (1560 hours) watching T.V.The average American will spend 60 hours on

HOLDThe average Englishman will spend 6 (36hrs/year) minutes a day laughing

Why Do We Sleep The Repair Theory – suggest that activities during

the day deplete key factors in our brain or body that are replenished or repaired by sleep.

Support (Sleep is needed to grow & create meaningful memories, repair its immune system and restore energy and chemicals During Stage 4 sleep marked secretion of growth

hormone

Increased production of of immune cells to fight infection

Glycogen is depleted during wakefulness and restored during sleep

Continued Adaptive Theory – suggests that sleep evolved because it

prevented early humans and animals from wasting energy and exposing themselves to the dangers of nocturnal predators Maximize our safety and survival

Ex. Taking a midnight stroll

Support - primarily from observing other animals (prey and predators) Lions – often, whenever, wherever (15 hours a day)

Many birds “unihemispheric sleep” Mallard Ducks

Seals and whales

Bats sleep 20 hours

The 2 Theories are not mutually exclusive

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Rhythm of Sleep

Circadian Rhythms occur on a 24-hour cycle and include sleep and wakefulness,

which are disrupted during transcontinental flights.

Light triggers the suprachiasmatic nucleus to decrease(morning) melatonin from the pineal gland

and increase (evening) it at night fall.

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2 major categories of Sleep

REM Sleep – Rapid Eye Movement When in REM sleep the eyes dart back and

forth

Non-REM Sleep – is where you spend approximately 80% of your sleep. It is divided into 4 Stages

Electroencephalogram (EEG)

REM Sleep Characteristics

Body and brain are in a general state of physiological arousal (blood pressure and heart rate may be 2x as high) – “paradoxical sleep”

Brain waves are very similar to Beta waves (awake)

Lose muscle tension in neck and limbs – essentially paralyzed – evolutionary advantageous

Makes up about 20% of sleep – pass through about 5-6 x

Remain in REM stage between 15-45 minutes

This is when we primarily are dreaming (80-90%)

REM rebound – refers to individuals spending an increased percentage of time in REM sleep if they were deprived of REM sleep on the previous nights.

Important Findings – Nader & Stickgold 2003 –suggests a correlation between REM sleep and store and encode memory

4 Stages of Non-REM Alpha Stage – marked by feelings of being relaxed and drowsy, usually

with eyes closed

Stage 1 (Theta waves)

Transition from wakefulness to sleep lasting 1-7 minutes

Lose responsiveness to stimuli and experience drifting thoughts and images

Arousal report having been awake

Stage 2 (1st Stage of Real Sleep)

Muscle tension, heart rate, respiration & body temp. drop

Sleep spindles

Minor noises won’t disturb you

Stage 3 & 4 (slow wave or Delta sleep)

Deepest stage of sleep – difficult to be awakened

Marked secretion of growth hormone

Sleep walking and talking occur during this stage of sleep

Changes during the Night

REM and Non-REM continues to alternate throughout the night

Stages 3&4 become shorter and REM tends to get longer and closer together

Although these cycles exist they are also irregular between people or within a given individual

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90-Minute Cycles During Sleep

With each 90-minute cycle, stage 4 sleep decreases and the duration of REM sleep

increases.

Sleep Deprivation

Stages of Sleep & Time Spent in Each Stage

Changes over Time to Sleep Type and Amount

Stages of N-REM & REM

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Accidents

Frequency of accidents increase with loss of sleep