ATAR Psych - Sleep U4

define sleep

the naturally occurring state of altered or reduced consciousness to external stimuli

purpose of sleep - evolutionary

1. we sleep to conserve energy to hunt/gather resources in the day

2. we sleep to reduce our vulnerability to predators in the night (bc its dark)

purpose of sleep - restorative

we sleep to maintain and recover our physiological bodily functions. e.g.

- restore hormone levels

- flush out waste toxins

- repair cells/tissues

- increase in protein synthesis

how long is a cycle of REM and NREM sleep?

90 mins

how many cycles of REM and NREM do we go through each night?

4-6

define sleep wake cycle

the recurring pattern of wakefulness & sleep we experience on a daily basis

NREM 1

- 2-10 mins

- heart rate is normal

- drifting in and out of sleep (easy to wake)

- muscles relax, may twitch or jerk

- eye movement slows

NREM 2

- 20-30 mins

- heart rate is slowed

- light sleep

- muscles are relaxed

- eye movement stops

NREM 3

- 20-30 mins

- heart rate is slowest

- deep sleep

- very relaxed (hardest to wake)

- minimal eye movement

REM

- every 90 mins, for 10-30 mins

- heart rate is fast

- light sleep

- voluntary muscles inhibited to prevent unwanted movements

- fast movement of eyes

Characteristics of REM Stage

- Brain is highly active

- Eyelids move rapidly side to side

- Heart rate & blood pressure increase and fluctuate

- Voluntary muscle movements are very relaxed/inhibited, except for small twitches

- Dreaming & memory consolidating usually occurs

what stage does physical restoration occur?

NREM 3

Characteristics of NREM Stage

- Brain activity slows down

- Eyes have little/no movement

- Heart rate & blood pressure slow down

- Muscles relaxed, but are not paralysed

- Physiological restoration usually occurs, including protein synthesis, release growth hormones and strengthen immune system.

Partial Sleep Deprivation

getting some sleep within a 24 hour period, but the length or quality of sleep is not sufficient for an individual to meet their needs

Chronic Sleep Deprivation

getting less than the optimal length and quality of sleep over an extended period of time.

mood disturbances

- is a psychological effect of partial sleep deprivation

- emotional responses are more amplified, more stress & feelings of negative emotions, more irritability

reduced attention

- is a psychological effect of partial sleep deprivation

- reduced focus & lack of motivation to complete tasks. One may face problems performing tasks, simple monotonous tasks and ones requiring sustained attention or concentration

slower reflex speed

- is a physical effect of partial sleep deprivation

- slowed reaction time, responses to stimuli is weakened and less accurate.

blurry vision

- is a physical effect of partial sleep deprivation

- blurry vision and difficulty in focusing eyes. peripheral vision is reduced (harder to notice things at the edges).

Insomnia

- is a psychological effect of chronic sleep deprivation

- the body gets "trained" into poor sleep cycles, making it harder to fall asleep or stay asleep, even when tired.

anxiety

- is a psychological effect of chronic sleep deprivation

- lack of rest heightens activity in the amygdala (fear/emotion centre), worsening stress, worry, and emotional instability.

heart disease

- is a physical effect of chronic sleep deprivation

- increases blood pressure, raises stress hormones (like cortisol), and disrupts heart rhythm → higher risk of cardiovascular disease and stroke.

obesity

- is a physical effect of chronic sleep deprivation

- alters appetite-regulating hormones leading to overeating and weight gain.

sleep hygiene

the habits, behaviours and environmental factors that can be adjusted to help a person receive healthy sleep

how to improve sleep hygiene

1. management of electronic devices

2. consistent sleep patterns

3. creating a healthy sleep environment

Management of electronic devices [sleep hygiene]

1. reducing screen time one hour before bed and using a blue light filter/night mode

2. engage in relaxing activities (e.g. reading a book, mediation, etc) away from devices, to activate the brain’s parasympathetic nervous system before bed

3. remove devices from the bedroom to eliminate the temptation to check notifications before bed

consistent sleep patterns [sleep hygiene]

1. set fixed bedtimes and wake times (at the same time every day, including weekends) to help regulate the body's internal clock (circadian rhythm)

2. avoid large variations/ discrepancies in sleep schedules between weekdays and weekends

3. establish a consistent pre-sleep routine to signal your body to prepare for sleep (e.g. showering, reading a book)

creating a healthy sleep environment [sleep hygiene]

1. have a comfortable mattress and supportive pillow that suits your needs and sleeping style

2. keep bedroom at a cool temperature (15-20 degrees)

3. keep bedroom lightning dark and avoid any artificial lights (especially “cool” lights)

4. keep bedroom not quiet and not noisy

shift work [causes of bad sleep]

- most people who do shift work experience sleep deprivation

- people who work a night shift tend to be active & alert during the night when melatonin levels are naturally higher & adrenaline & cortisol level are lower.

- this disrupts our natural sleep & waking cycles, forcing you to be awake when you're meant to be sleeping

drugs [causes of bad sleep]

- stimulants like caffeine, nicotine, etc can stimulate the nervous system and delay the onset of sleep

- depressants like alcohol can reduce sleep quality by interrupting REM and deep sleep.

sleep environment [causes of bad sleep]

- noise, light, uncomfortable bedding, or using phones/screens before bed can prevent falling asleep or cause frequent waking up during the night

stressors [causes of bad sleep]

- high stress levels activate the sympathetic nervous system, making it difficult to relax & fall asleep.

- this is because you stay in bed worrying rather than relaxing, resulting in less sleep overall