Week 5- Sleep Flashcards
the cumulative effects of decreased sleep can lead to…
increased risk of hypertension, diabetes, obesity, depression. heart attack, stroke
% of serious car crashes that are attributed to diver sleepiness?
20%. this is the largest identifiable and preventable cause of accidents in all modes of transport
Why do we sleep?
not fully understood
animals fully deprived of sleep die therefore there is biological necessity
sleep is restorative( surge in GH, brain plasticity(forming new skills and memories), flushing metabolic waste from the brain)
necessary for proper functioning as lack of sleep is associated with illness and impaired function
4 main functions of sleep
conserve energy,enhance survival/adaptation, restorative/repair of injury(NREM), aid learning/memory consolidation(REM)
how much sleep do adults “need”?
>7 hours on a regular basis to promote optimal health
effects on sleep less than 7 hours on a regular basis?
this is associated with adverse health outcomes like weight gain, obesity, hypertnesion, heart disease and stoke, depression, increased risk of death.
Also associated with impaired immune function, increased pain, impaired performance
sleep more than 9 hours a night on a regular basis may be appropriate for…
young adults, indivs facing sleep debt, indivs with illness
Are there individual differences for sleep?
some can function on 6 but some need more 9. on average 7.5 should be aimed for
what are the 2 ways sleep can be meausred
Objecitvely and subjectively
objective sleep measurement
done via polysomnography( measures things like sleep latency, total sleep, sleep efficiency) and actigraphy( indirect measurements via an accelerometer, not always most efficient as it measures lack of movement)
subjetcive sleep meausrements
done via sleep diaries to report things like sleep latency, total sleep,awakenings etc. and self report questionnaires
Stages of sleep
- NREM
- Subdivided into 3 stages
- called quiet sleep in infants or synchronized sleep in animals
- REM
- originally JEM
- also called infants: active sleep, animals: desynchronised, paradoxical
parameters a PSG measures
What does an EEG measure?
looks at the difference in electrical potential between pairs of electrodes placed on the scalp and represents this as a voltage-time graph. the signals reflect postsynaptic potentials in neurons below the electrodes and these signals are amplified and filtered to produce digital/analog recordings
The EEG bands
beta waves 14-26 Hz/cps( alert waking, arousal from sleep)
alpha waves 8-13(relaxed walking, eyes closed, arousal from sleep)
theta waves 4-7(sleep onset, light sleep)
delta waves 0.5-3 (deep sleep)
as we get more to deep sleep, wave freq decreases
