Sleep Flashcards
consciousness
Differences in our level of awareness of our sensations, thoughts, feelings and surroundings influence our interactions with our environment and other people
consciousness as a psychological construct
consciousness is considered a psychological construct because it cannot be objectively observed or measured through the collection of data, but it is widely understood to exist
normal waking consciousness (ordinary consciousness)
a state of consciousness associated with being aware of both our internal and external environments
Altered state of consciousness (ASC)
Any state of consciousness that differs in awareness when compared to NWC.
Divided into:
Naturally occurring and induced
naturally occurring ASC
An altered state of consciousness that occurs without any external influence.
induced state ASC
An altered state of consciousness that is intentionally retrieved with an aid (e.g meditation, hypnosis, alcohol etc)
Electroencephalograph (EEG)
Electromyograph (EMG)
Electro-oculargraph(EOG)
EEG: a device that detects, amplifies and records general patterns of electrical activity of the BRAIN over time.
EMG: a device that detects, amplifies and records the electricalactivity of muscles.
EOG:measures eye movementsor eye positions by detecting, amplifying and recordingelectrical activity in eye muscles that control eyemovements.
Frequency
refers to the number of brainwaves per second.
High-frequency brain waves = more per second.
Amplitude
refers to the intensity of brain waves, and can be measured through the peaks and troughs visually seen in an EEG.
Higher-amplitude brain waves = higher peaks and troughs.
brain wave types
relate to the person’s level of awareness or state of consciousness
as the frequency of a brain wave decreases, the amplitude increases.
As a person drifts into the deeper sleep stages of a sleep cycle, their brain wave activity decreases, as indicated by progression through the four brain wave types.
Non-Rapid Eye Movement (NREM) sleep
A type of sleep characterised by a progressive decline in physiological activity.
Takes up 80% of a sleep episode
NREM 1
relatively light sleep
physiological responses begin to slow down (brain activity, heart rate, body temperature)
amounts to 4 or 5% of total sleep time
people are easily awakened
NREM 2
light sleep, sometimes described as moderate sleep because it gradually becomes deeper
continued slowing of heart rate, breathing, muscle activity and body movements.
Body temperature continues to fall and eye movements stop.
N2 has a higher arousal threshold than N1
NREM 3
deep sleep
heart rate and breathing slow to their lowest levels, muscles are completely relaxed and we barely move
largest and slowest brain waves (delta waves are prominent)
highest arousal threshold
a person may spend between 20-40min in N3 (depending on age)
makes up 10 to 15% of total sleep time
REM sleep
defined by spontaneous bursts of rapid eye movement
20-25% of total sleep time
also called paradoxical sleep - internally brain and body are active, while, externally, the body appears calm and inactive
dreaming
most dreaming occurs during REM sleep
dreams that occur in NREM sleep stages are generally shorter, less frequent, less structured, less likely to be recalled and less vivid than REM dreams
REM dreams typically have a narrative structure and consist of storylines that can range from realistic to complete fantasy
four internal biological mechanisms that influence the regulation of our sleep–wake patterns
circadian rhythm
ultradian rhythm
suprachiasmatic nucleus
melatonin
circadian rhythm
biological processes in all animals that coordinate the timing of activity of body systems over a 24-hour period.
ultradian rhythm
biological processes that coordinate the timing of activity of body systems over periods of less than 24 hours.
e.g heart rate, pulse, appetite
suprachiasmatic nucleus
master body clock in the hypothalamus that regulates body activities to a daily schedule of sleep and wakefulness
zeitgebers
external environmental cues such as light, temperature and eating patterns that can synchronise and regulate the body’s circadian rhythm
melatonin
Hormone that is involved in the initiation of sleep and in the regulation of the sleep-wake cycle (induces drowsiness and decreases cell activity).
trends across the lifespan
- The total amount of sleep decreases.
- The proportion of REM sleep decreases significantly from birth until 2 years old.
- The amount of N3 sleep decreases, replaced mostly by N2 sleep.
- A circadian phase delay occurs during adolescence (preference for going to sleep later).
After adolescence, a shift to a circadian phase advance occurs (preference forgoing to sleep earlier).
- Awakenings during sleep increase from adulthood to old age.
- Sleep efficiency (the percentage of the time in bed that is spent asleep)reduces.
newborns and infants
No established circadian rhythm
In the first 2 weeks of life, 50% of the infant’s sleep is REM sleep
By 12 months, 14-15 hours total sleep time, mostly occurring in a single episode at night
children
total sleep time continues decreasing as the child gets older, from about 13 to 11 hours between 2 to 5 years of age
proportion of REM sleep continues to decrease (20%) and the amount of NREM sleep increases, with a greater percentage of sleep time spent in stages 2 and 3
adolescents
total time spent sleep decreases, as does amount of REM sleep (20%)
By mid adolescence, sleep episode resembles that of young adults
Adolescents tend to get less sleep then they need to function at their best (partly due to sleep-wake cycle shift)
adults
average of 8hrs of sleep per night, 20-25% REM
Overall pattern of sleep shows a progressive decline in the duration of a typical sleep episode and in the proportions of time spent in REM and NREM sleep.
There is also a gradual loss of NREM stage 3 sleep.
As an individual ages (between the ages of 20 to 60), deep sleep declines at a rate of about 2% per decade. By age 60 or so, a severe reduction is evident.
older adults (65+)
less NREM stage 3
Eventually, stage 3 disappears altogether.
REM (18-20%)
Sleep becomes fragmented, with more night time awakenings (due to less N3 sleep)
7-8 hours sleep each day
some have 30 minute naps
sleepier in the early evening and wake earlier in the morning
partial sleep deprivation
involves having less sleep (either quantity or quality) than what is normally required.
total sleep deprivation
involves not having any sleep at all over a short-term or long-term period.
sleep debt
the accumulated amount of sleep loss from insufficient sleep.
sleep deprivation: affective functioning
emotions and mood
trouble regulating or controlling your emotions.
amplified emotional responses / unwarranted emotional outbursts
mood swings
Be more irritable or cry for no apparent reason.
sleep deprivation: behavioural functioning
refers to a person’s observable actions
One of the immediate effects on behavioural functioning can be sleep inertia — a temporary period of reduced alertness and performance impairment that occurs immediately after awakening.
- Excessive sleepiness
- Fatigue
- Slower reaction time
- Increase in risk-taking behaviour
microsleep
a sleep episode that lasts for a few seconds
unintended / involuntary
sleep deprivation: cognitive functioning
refers to a person’s mental processing
cognitive functioning issues:
- trouble with memory
- decreased alertness
- poor concentration
- impaired problem-solving, decision making
- poor judgement
- lack of motivation
cognitive effects of sleep deprivation v BAC
17hrs = 0.05% BAC
24 hrs = 0.10% BAC
circadian rhythm sleep disorders
a category of sleep disorders characterised by a persistent pattern of sleep disruption due to a misalignment between the circadian rhythm and the sleep–wake schedule required by a person.
3 types: DSPS, ASPD, SWD
Delayed Sleep Phase Syndrome (DSPS)
a circadian rhythm sleep disorder characterised by a delay in the timing of sleep onset and awakening, compared with the timing that is desired or conventionally accepted.
Advanced Sleep Phase Disorder (ASPD)
a circadian rhythm sleep disorder characterised by an advance in the timing of sleep onset and awakening compared to the timing that is desired or conventionally accepted
Shift Work Disorder
a circadian rhythm sleep disorder that occurs as a result of work shifts being regularly scheduled during the usual sleep period.
Treating circadian rhythm sleep disorders
Bright light therapy, also called phototherapy, involves timed exposure of the eyes to intense but safe amounts of light. When used for circadian rhythm sleep disorders, the aim is to shift an individual’s sleep–wake cycle to a desired schedule, typically the day–night cycle of their physical environment.
Bright Light Therapy and DSPS
light exposure generally takes place during the early morning hours (e.g. between 6–8 am) to help advance the circadian rhythm to an earlier time
Bright Light Therapy and ASPD
light exposure takes place early at night/in the evening to help delay the circadian rhythm to a later time (i.e. shift the phase backward) so that the person will be sleepier later and wake up later.
sleep hygiene
practices that tend to improve and maintain good sleep and full daytime alertness.
good sleep hygiene practices
Establish a regular relaxing sleep schedule and bedtime routine.
Associate your bed and bedroom with sleep. (don’t study in bed!)
Avoid activities that are stimulating in the hour before bed. (exercise, digital devices, etc.)
Avoid napping during the normal waking period.
Avoid stimulants such as caffeine, nicotine and alcohol too close to bedtime.
Exercise during the day to promote good sleep (preferably more than 4 - 5 hours before sleep)
Don’t eat right before bed (eat at least 2 hours before bed)
using zeitgebers to improve sleep
zeitgebers are environmental cues, such as light, temperature and eating patterns that can synchronise and regulate the body’s circadian rhythm
exposure to daylight
exposure to daylight during the morning hours and early afternoon advances the sleep-wake cycle, pushing it forward to a slightly earlier time. Light exposure in the late afternoon and early evening has the opposite effect, delaying the sleep-wake cycle and pushing it back to a later time
temperature
Air temperature can be used as a zeitgeber to signal and help get the body ready for sleep, but probably with a weaker strength than light
sleep is most likely to occur when core body temp decreases
eating and drinking patterns
For most people who routinely consume food during the active, daylight phase of the 24 hour cycle, the suprachiasmatic nucleus and peripheral clocks remain synchronised, allowing for a consistent and appropriate sleep-wake cycle
adjusting eating and drinking patterns
bringing meal times back to a normal schedule during the active, light phase of the day, as well as leaving a sufficiently long fasting window during the circadian inactive phase of the night, will allow the peripheral clocks to resynchronise with the suprachiasmatic nucleus
