ALTERED STATES OF AWARENESS Flashcards
altered states
our state of awareness is constantly changing and affects our ability to function in different situation
Affected by how much sleep we get, and our level of physiological and psychological stress.
circadian rhythms
a behavioural or physiological cycle that takes place over a 24 hour period.
controlled by areas in the brain
circadian rhythm examples
Body temp: generally peaks in the afternoon and at lowest in early morning – drop in body temperature in the evening coincides with a drop in alertness.
Sleep/wake cycle
Humans level of alertness at lowest in early hours of the morning and peak in the late afternoon.
zetigebers
Zeitgebers are environmental cues that impact your circadian rhythm and energy levels throughout the day.
Zeitgebers all send “time keeping” clues to your brain that resets your circadian rhythm
Zeitgebers examples
exercise, sunlight, sleep debt, eating, shift work, interest levels, social contact
most obvious zeitgeber is daylight
SCN (suprachiasmatic nucleus)
the sleep/wake cycle is controlled by the SCN
SCN is a “biological clock” that keeps track of time of day
(sends messages to the brain and body)
light is the main external cue that syncs this clock
Jet lag
The SCN recognises the time of day to be different from what external cues tell us. Due to travelling through several time zones.
A circadian related problem and results in reduced quality of sleep
On average, it takes one day of adjustment for every hour of time zone change
- 5 hour time difference = 5 days for circadian rhythm to adjust.
symptoms of jet lag
Daytime sleepiness
Increase fatigue
Loss of concentration
Increased irritability
Jet lag facts
Body adjusts more easily if bedtime is delayed than if brought forward.
Sports people need to manage their jet lag in order to increase/maintain their performance.
Strategies to minimise effects of jet lag
Live on destination time before departing
Strategise when to sleep on journey (sleep according to destination night time)
Sync circadian rhythm of eating to destination time
Delay sleep if arriving in the daytime
sleep stages
Sleep is made up of 5 stages, each with different characteristics.
4-6 sleep cycles each night, and each cycle last around 90-110 minutes.
STAGE 1
Described as ‘relaxed wakefulness’ Brain: - Alpha brain waves present on EEG - Reduced brain activity - Irregular, fast and slow amplitude EEG
Body:
- Rolling eye movements
- Slowed breathing and heart rate
- Reduced muscle activity
- Hypnotic jerks
Last approximately 10 minutes
STAGE 2
Brain:
- Presence of sleep spindles and K-complexes
Body:
- Medium amplitude in muscle movement
- No eye movement
- Temperature, heart rate, breathing and blood pressure continue to drop
Last about 20 minutes
STAGE 3 - SWS
Brain:
- Slow waves appear called Delta waves
- Travel to stage 4 (deepest stage)
- Delta waves make up 20 – 50% of brainwave activity
Body:
- Medium to low amplitude in muscle tension
- No eye movement
- Heart rate, breathing, blood pressure and temperature continue to drop
Lasts about 15 minutes
STAGE 4 - SWS
Deepest stage of sleep
Brain:
- Delta waves account for more than 50% of brain wave activity
Body:
- Little to no muscle movement
- No eye movement
- Breathing at its slowest and deepest
- Hard to wake someone from this stage > if awoken person is confused and disorientated
Amount of SWS > how restored a person feels
Stage 3 and 4 combined lasts about 30 mins
STAGE 5 - REM
Sleep ‘lightens’ and moves back through stages 4-3-2 to a unique stage (REM)
‘Rapid eye movement’ > eyes moving around
Brain:
- People report ‘dreaming’
- EEG in REM similar to an awake person
- Beta and some alpha waves present
Body:
- Pulse, breathing, blood pressure quicken
- Eyes move around very quickly
Deepest sleep in first cycle > dream sleep in last cycle
sleep debt
build up of the difference between the amount of sleep that a person needs to function at an optimal level and the amount they actually have.
E.g. if a person needs 8 hours each night but only gets 7, they have a sleep debt of 1 hour.
Our desire to sleep during the day increases the more sleep debt we have.
sleep deprivation
When a person does not get the required amount of sleep to function at the optimal level.
Has a negative effect on our bodies by reducing the effectiveness of our immune system.