AOS 1 SAC: SLEEP

sleep hygiene

good habits and practices that support consistent, restful, and high quality sleep

Key sleep hygiene strategies (6)

1. Consistent Sleep Scheulde - regulates the circadian rhythm

2. Use your bed only for sleep- builds strong psychological connection to sleep

3. No screens 1 hours before bed- these disturb natural sleep cycles- blue light interferes with melatonin production

4. Avoid Caffeine and alcohol before bed-disturbs natural sleep cycles

5. Relaxation before bed-reduces arousal and helps sleep onset

6. Exercise Daily (not too close to bedtime)- builds sleep pressure, improves quality

Zeigebers

external environmental cues that help synchronise our interal body clock with the external world

main types of zeigebers

• Light based - daylight, blue light, artificial light

• Social/ Behavioural- meal times, routines, social interaction, exercise

Adapting to light Zeigeber

• morning sunlight exposure resets circadian rhythm

• avoiding blue light at night allows melatonin to rise nauturally

  TIP: get 10-30 mins natural light after waking, to help reset sleep-wake cycle

Adapting to temprature Zeigeber

• sleep is easier when body temp is cooler

• warm shower 1 hour before helps trigger natural body cooling

• ideal room temp 18-20

adapting to eating pattern zeigeber

• avoid heavy meals, caffeine, and alcohol before sleep

• eat at consistent times to reinforce daily body rhythms

Circadian Rhythm Disorder

when your body’s internal clock is out of sync with societal expectations

Circadian Rhythm Disorders usually cause

• insomnia

• excessive sleepiness at the wrong time

• daytime fatigue

Types of circadian rhythm sleep disorders

• Delayed Sleep Phase Disorder (DSPS)

• Advanced Sleep Phase Disorder (ASPD)

• Shift Work Disorder

DSPS problems

• “Night Owl” Problem

• very late sleep schedule (3am-11am)

• can’t fall asleep and struggle to wake up in the morning

DSPS symptoms

• can’t fall asleep until late

• struggle to wake for school/ work

• feel very sleepy in the morning

• normal sleep quality, just shifted too late

why does DSPS happen (3)

• cicadian rhythm wants a later bedtime

• very common in teenagers

• can become a real issue when responsilities (like school) don’t match

ASPD problems

• “early bird” problem

• very early sleep schedule (6pm-2am)

• get super sleepy in the evening and wake up too early

ASPD symptoms

• can’t stay awake in the evening

• wake up way too early (and can’t fall back asleep)

• tired during the day

Possible causes of ASPD

• weaker body clock (SCN)

• lower melatonin production

• less exposure to light in the evening

Shift Work Disorder problems (SWD)

• “I work nights” problem

• you work night shifts or rotating shifts- confuses your circadian rhythm

SWD symptoms

• can’t sleep well during the day

• feel tired at work in the night

• insomnia + excessive sleepiness

Why is SWD so bad

• you’re awake when your body naturally wants to sleep

• sleep is light, short, and easily disturbed

• may get 1-4 hours less sleep than normal

risks of SWD

• sleep debt

• low alertness= more accidents

• worse when shifts rotate quickly (e.g. every few days)

• long-term health issues

Bright Light Therapy (Phototherapy)

helps to reset biological clock (SCN) using artificial light

how bright light therapy works

• you sit near a light box that mimics sunlight (at least 2500-10,000 lux)

• sessions last 15 minutes to 2 hours

• can be done reading or using your phone

when someone with DSPS should do BLT

use light early in the morning to shfit circadian rhythm earlier

when someone with ASPD should do BLT

use light in the evening/night to shift circadian rhythm later

when someone with SWD should do BLT

evening or before shift to help you stay alert at night

17 hours awake to BAC

0.05%

24 hours awake to BAC

0.10%

Dawson and Reid Study (1997)

• 40 participants

• within-subjects design with counterbalancing

• 2 conditons: sleep deprivation and alcohol consumption

• both groups had to complete computer tasks that tested hand-eye coordination, attention, speed, accuracy, decision making

Cognitive effects from Dawson and Reid Study

as time increased, performance dropped

one full night without sleep can impair thinking as much as being drunk

Affective effects from Dawson and Reid Study

Both sleep deprivation and alcohol can

• make you moody, irritable, or short-tempered

• affect your motivation and emotional regulation

• interfere with your focus, memory, and decision-making

examples of the connection between alcohol consumption and sleep deprivation

• being in a bad mood might make you drink more

• drinking can affect your sleep

• poor sleep can worsen your mood- and the cycle continues

real life application of dawson & reid study

• sleep-deprived people may be just as unsafe as drunk people when driving or working

• teenagers are especially vulnerable to sleep loss due to late bedtimes, study pressure, and social media

• always be cautious about your sleep habits, especially before doing important tasks like exams, work, or driving

Sleep Deprivation

when a person gets less quantity or quality of sleep than needed

voluntary deprivation example

staying up late to watch a sport game or to play a video game with friends

involuntary deprivation example

working night shifts or having a sleep disorder

partial sleep deprivation

getting some sleep, but not enough

total sleep deprivation

getting no sleep at all for a period of time

sleep quantity

how much sleep you get (measured in hours)

sleep quality

how well you sleep- measured by how restored or rested you feel, and whether your sleep was consolidated (not interrupted)

Sleep debt

accumulated sleep loss over time

e.g. sleeping 1 hours less for 5 nights = 5 hours debt

repaying sleep debt

• one good sleep (sufficent quality/quantity) can repay the debt

• you don’t have to repay debt fully, but need enough recovery sleep to function well

3 main effects of partial sleep deprivation

• Affective functioning (Emotions and mood)

• Behavioural functioning (actions and physical responses)

• Cognitive Functioning (thinking and mental processing)

effects of partial sleep deprivation on Affective functioning

• people become irritable, moody, or emotionally reactive

• emotional regulation is impaired- tend to overreact or respond inappropriately

• harder to read other peoples’ emotions or show empathy

examples of effected Affective functioning

• snapping a friends

• misreading social cues

• feeling overwhelmed easily

effects of partial sleep deprivation on Behvioural functioning

• slower reaction time, reduced motor skills, more mistakes

• more risky behaviour- crossing roads dangerously, especially when distracted

• more school lateness, injuries, inattentiveness, and disruptive behaviour in kids

sleep inertia

grogginess after waking up- can last minutes to hours and affects alertness

excessive sleepiness

trouble staying awake, feeling drowsy during the day

fatigue

low energy and reduced motivation

microsleeps

brief, involuntary episodes of sleep (1-15 seconds)

can be extremely dangerous if driving or working

effects of partial sleep deprivation on Cognitive functioning

• attention is impaired- especially boring or repetitive tasks

• harder to do complex thinking, make decisions, or solve problems

• trouble with simple, monotonous tasks

• impaired memory- trouble encoding

• problems with short-term memory

factors influencing sleep deprivation (5)

• how much sleep was lost

• when and why the loss occurred

• how often it happens

• for how long it continues

• the person’s age, health, lifestyle

sleep disturbance

any problem that interrupts your normal sleep-wake cycle, such as:

• trouble falling asleep

• waking up too often during the night

• unusual behaviours during sleep

sleep disorder

more serious than just one-off bad night, it

• happens often

• distrupts sleep patterns

• interferes with everyday functioning (e.g. feeling tired/moody/unmotivated)

types of sleep disorders

• primary

• secondary

primary sleep disorder

• sleep issue is the main problem

• not caused by another condition

• e.g. insomnia

secondary sleep disorder

• sleep problem is a symptom of another issue

• could be caused by medical issues, mental health, drugs

• e.g. poor sleep due to chronic back pain or anxiety

sleep problems can affect

• your emotion (mood swings, irritability)

• change your behaviour (slower reaction, poor performance)

• hurt your thinking (poor memory, lower concentration)

risks of ongoing sleep problems

• mental illness

• physical health issues/ problems

Main changes in sleep over lifespan

1. total sleep time decreases with age

2. REM sleep drops quickly after birth, then stays fairly stable

3. NREM stage 3 gradually decreases with age- can disappear especially in men

Sleep in newborns & infants (0-2 years) (6)

• approx 16 hours a day (in short bursts)

• REM = about 50% of total sleep

• shorter cycles, only 1 or 2 per episode

• sleep onset often starts in REM

• very active REM

• circadian rhythms not developed until 2-3 months

sleep in children (2-10 years)

• 11-13 hours a day

• NREM stage 3 is very high

• hard to wake during stage 3

• may skip first REM cycle due to strong deep sleep early in the night

sleep as children grow

• REM % slighty decreases

• deep sleep starts to reduce after about 10 years

sleep in adolescents (10-18 years)

• about 9-10 hours

• biological sleep-wake shift → feel sleepy later

• lifestyle = less sleep

• irregilar sleep patterns

• stage 3 sleep drops about 40%

most teens are sleep deprived due to

• internal factors

  • biological clock shift

• external factors

  • school, tech, social life

Sleep in Adults (18-60 years)

• about 7-8 hours

• 20-25% REM sleep

• stage 3 sleep gradually decreases

• by age 60, half as much stage 3 as at 20

• stage 3 can disappear entirely

• sleep becomes more fragmented (light, frequent waking)

Older adults (60+ years)

• about 6 hours sleep

• little to no stage 3 sleep

• mostly stage 2 sleep

• sleepier earlier in the evening, wake earlier

• frequent naps- sleep often interrupted

why do older adults wake often throughout the night

• less deep sleep

• health issues, meds, reduced melatonin

• less exposure to natural light & social cues

NREM Sleep

a type of sleep characterised by a lack of rapid eye movement, and subdivided into three different stages

REM Sleep

type of sleep characterised by rapid eye movement, high levels of brain activity, and low levels of physical activity

sleep cycle features

• each lasts around 90 mins

• cycle includes

  • NREM stages 1 → 2→ 3→2

  • then REM sleep

sleep cycles as night progresses

• stage 3 (deep sleep) decreases

• REM sleep periods become longer and more frequent

NREM Stage 1 (N1)- light sleep (6)

• entry into sleep → transition from wakefulness

• duration is about 5 mins (4-5% of total sleep)

• brain waves: theta

• low arousal threshol- easy to wake

• heart rate and body temp drop; hypnic jerks may occur

• may feel like you haven’t slept if woken

NREM Stage 2 (N2)- light/moderate sleep

• 10-25 mins at first → increases in later cycles

• slower brain waves, sleep spindles, and K composition

• harder to wake than N1

• makes up about 50% of total sleep

NREM Stage 3 (N3)- deep sleep

• about 20-40 minutes in the first cycle, less in later ones

• over 50% delta brain waves

• highest arousal threshold → very hard to wake

• sleep interia if awoken

• important for physical restoration, immune system, growth hormon release

• make up about 10-15% total sleep

REM Sleep

• about 20-25% total sleep

• brain is very active, similar to being awake (beta-like waves)

• body experiencing paralysis of skeletal muscles, except eyes and small twitches

• breathing, heart rate, blood pressure increase and often irregular

• dreaming very common

REM Dreams

narrative, vivid, emotional

NREM Dreams

more thought-like or abstract

Sleep latency

time it takes to fall asleep after trying

Sleep onset

moment a person transitions from awake to asleep

Hypnic Jerk

sudden muscle spasm as you fall asleep (N1)

Sleep inertia

grogginess/ confusion after waking from deep sleep

delta waves

slow, high-amplitude brain waves (seen in N3)

paradoxical sleep

REM Sleep- high brain activity, paralysed body

biological rhythms

natural, repeating cycles in the body and brain

controls physical functions and behaviours

biological clocks

internal timers that regulate rhythms

found in nearly every cell

“Master Clock”

located in the brain and coordinates all the body’s clock to keep them in sync

Circadian Rhythms

approx. 24 hours

endogenous but influenced by exogeneous cues like light, clocks, meals

e.g. sleep wake cycle, body temprature, cortisol levels

Suprachiasmatic Nucleus (SCN)

structure in hypothalamus that regulates an individual’s sleep-wake pattern and helps to release melatonin

controls circadian rhythm

pineal gland

responsible for the production and release of melatonin

Ultradian Rhythms

less than 24 hours

e.g heart rate, breathing, eating pattenrs, hormone bursts

sleep cycle is a key rhythm

Sleep as an ultradian rhythm

• one cycle is about 90 mins

• repeats 4-6 times a night

• alternates between REM and NREM sleep

Suprachiasmatic Nucleaus Features

• located in hypothalamus

• master biological clock

• recieves light info from optic nerves

• sends signals to the pineal glands to control melatonin production

How does the SCN help to regulate sleep-wake cycle

• light is detected by the eyes

• stimulates the SCN in the brain

• SCN sends signal to the pineal gland

• melatonin hormone is released to the brain

Meltonin

• hormone that make the brain feel sleepy

• produced by the pienal gland, regulated by the SCN

• more meltonin= more drowsy

• less light= more melatonin

• morning light= melatonin drops= wakefulnes

• often referred to as “dracula of hormones”- only come out in the dark

objective

not influenced by personal feelings or opinions in considering or representing facts

subjective

based on or influenced by personal feelings, tastes, or opinions

Physiological Measurements (Objective)

used to gather quantitive data on the body’s internal functions during sleep

• brain acitivty (EEG)

• muscle activity (EMG)

• eye movement (EOG)

• heart rate, breathing, temprature, body postition, snoring, etc.

Sleep Diaries (subjective)

used for self-reporting patterns of sleep/ wake behaviour

• bedtime

• quality of sleep

Video Monitoring

used to observe external behaviours during sleep

• sleepwalking

• movements

• nightmares

Electroencephalogram (EEG)

measures electrical activity in the brain