Lecture 4-6 Flashcards
What is the restorative theory of sleep?
- rest, recuperation
- repair effects of daily wear & tear
- physiological processes restored
- growth hormone released from pituitary: increased cellular division & RNA synthesis
- REM: protein synthesis, increases after learning
- N3 taxed in learning
What is the memory consolidation & learning theory of sleep?
- consolidation & facilitation of long-term memory
- brain rehearses newly learned info in N3
- declarative/explicit memory = N3 needed
- nondeclarative/implicit memory = REM needed
What is declarative/explicit memory?
- conscious recall
- semantic (concepts, facts, landmarks) + episodic (experiences, events)
What is nondeclarative/implicit memory?
- unconscious recall
- procedures, how to’s, motor skills, habits (throwing a ball, learn to drive, recognise faces)
What is the adaptive, survival theory of sleep?
Sleep patterns due to:
- predator or prey
- when can see optimally
- caloric use:
- sleep = less calories, less food
- awake when food most available
- environment:
- prevent drowning, sinking, danger
- cerebral hemispheres “take turns”
- move to warmth/cold
- safe, preferred sleeping location
- integrated into annual cycles: hibernation, reproduction
What is the energy conservation theory of sleep?
small animals: high metabolic rate - sleep longer with shorter NREM-REM cycles
larger animals: slower metabolic rate - sleep less, longer NREM-REM cycles
What is sleep like in mammals, birds, reptiles, amphibians, fish & invertebrates?
- > 90 species of mammals studied
- closer to humans = more similarities
- all reptiles and birds exhibit N3 & REM but species dependent
What is a sleep feature in birds?
less REM than mammals, except predator birds
What is a sleep feature in owls, moles & opossums?
no eye movements
What is a sleep feature in dogs, wolves, rabbits & birds?
not complete REM paralysis, much eye movements
- phasic eye movement
What is a sleep feature in reptiles, tortoises & turtles?
high amplitude spikes during sleep
- is it sleep or cold blooded torpor (physical & mental inactivity)?
What is sleep like in sea dwelling or migratory animals?
- cannot “settle” to sleep, surface breathing, flying long distances
- bottlenose dolphins, porpoises, pigeons, mallard ducks
- asynchronous brain sleeping
- large sea mammals: hold breath and sleep for 30mins, wake to surface & return down
What is asynchronous brain sleeping?
- one cerebral hemisphere at at a time
- half-brain in N2-N3, while other awake with opp. eye open; one hour each side
What is sleep like in bears, caterpillars & frogs?
hibernation:
- extreme lowering of body temp, metabolic rate, respiration, with short periodic bouts of rise over several weeks
- no/little recordable EEG
hibernation complete:
- sleep for extended period with increase in N3
What is sleep like in fruit fly, marine snail, scorpions, cockroaches & jellyfish?
quiescence & activity
What is sleep like in infants?
- newborn brain immature to produce adult EEG wave patterns
- AS, QS, IS
- healthy newborn: 16-18hrs, >50% in AS
- late term or premature: >75-80% in AS
- enter AS right after falling asleep
- distribution of sleep-wake numerous in nychthemeron
- QS & AS alternate in 50min cycles, increasing in time till 5mths old
- AS = REM at 3mths; QS = N3 at 6mths
What is active sleep (AS)?
low-voltage, irregular EEG, eye movements, low-high EMG, no motor paralysis; first smile
What is quiet sleep (QS)?
EEG similar to adult N3, no eye movement, mid-lower EMG, absence of body movements
What is intermediate sleep (IS)?
mixture of quiet and active
What is a nychthemeron?
period of 24 consecutive hours
What is sleep like in early childhood?
- 2-3mths: able to sleep thru night, w/ daytime naps
- 3mths: 40-50% in REM
- 5mths: at least 50% of infants sleep when parents sleep
- 8mths: 33% in REM, sleep 13-14hrs
- between 1-2 years: REM stabilizes at 25%, same as young adult
- 3-5 yrs: sleep 10-13 hrs & daytime napping ceases
What is the theory for early childhood sleep?
REM important to neural/nervous system maturation; needs stimulation
What is sleep like in children?
- NREM-REM cycle: 60mins
- enter N3 quickly, stay for 1hr, then arousal-sleep EEG, skip first REM
- position changes
- first REM 10-20mins, w/ subsequent periods 20-25mins
- by 10yrs: cycles resemble adults, but sleep 10hrs
- pre-teen (12-13yrs): fall asleep quickly, v. deep N3, v. difficult to wake
What is sleep like in adolescence?
- need 9+hrs per nycthemeron
- obtain 6-8hrs (+ sleep in, weekends): signs of sleep debt & deprivation
- 25% in REM
- circadian phase delay to later sleep hours
- vs. school times & learning expectations
What is sleep like in adults?
- fatal familial insomnia, death in 12-18mths
- average 7hrs, standard deviation of 1 hr
- 2/3 of population: 6.5-8.5hrs
- 16% of pop. 8.5+hrs, 16% of pop. <6.5 hrs
- minority: sleep <5 hrs regularly & healthy
- growing concern: ppl sleeping less
What is fatal familial insomnia?
prolonged sleep deprivation, inherited/passed down thru genes
What is sleep like in older adults?
- sleepier in day, less impact of sleep debt/deprivation
- difficult sleep onset, sleep less at night & fragmented, but naps
- sleepy in evening, awake in morning
- 48-50yrs: 4-6 hrs, N3 decline
- 50-60yrs: N3 diminish, 5-10% of sleep
- 85-90yrs: N3 disappears
- Alzheimer’s
- REM: some decrease, but maintained into extreme old age
- more REM earlier in night, more N1 sleep
What is Alzheimer’s?
marked reduction in N3
- theory: deterioration/less growth requirements of brain cells, cognitive abilities
- study results: long term sleep debt could cause Alzheimer’s
What are the differences between sleep in women & men?
women:
- go to bed earlier, fall asleep sooner, sleep longer
- more awakenings & time awake in each cycle
- “aging-related sleep changes”: 10 yrs later, 2x sleep spindles, slower N3 decline
- older women: longer to fall asleep, poorer quality & nap more
What are factors that affect women’s sleep?
- menstrual cycle: natural cyclic progesterone increases sleepiness & speeds sleep onset, estrogen increases REM length
- oral contraceptives: increase melatonin levels & body temp, shift into REM quicker
- menstruation: bloating & pain interrupts sleep
What is sleep like during pregnancy?
- metabolic changes, discomfort
- 1st trimester: increased sleepiness, disturbed sleep, blood volume doubles
- 2nd trimester: “grace period”
- 3rd trimester: more & longer awakenings; N3 declines approaching absence
- following birth: recovery from delivery, irregular sleep schedule, breastfeeding, postpartum depression
- 6mths to 1yr to recover most aspects of sleep, sleep efficiency remains low & number of awakenings high into childhood
What is sleep like during menopause?
- production of progesterone & estrogen decline, cease
- 40-75% of women complain of sleep issues
- hot flashes: 1.5-5yrs typical = brief arousals, >100 awakenings
- insomnia & sleep-disordered breathing
- hormone replacement therapy: help w/ some symptoms/sleep time, increase sleep quality
- lasts few years
What is phase shifting?
phase advancing/delaying
- advancing: shift biological clock forward to earlier time
- delaying: shift biological clock back to later time
What are sleep hour preferences?
- Morning Type (MT)
- Evening Type (ET)
- Neither Type (NT)
- genetic disposition, developmental/established habits
- teens become ET, gradually NT, MT characteristics seen by middle age
- questionnaire (Horne and Ostberg): time of day you rise, prefer to rise, feel your best, had to sleep at different times
What are the characteristics of MT?
- fall asleep more easily, better moods
- wake more during sleep
- more women tend to be MTs than men
What are the characteristics of ET?
- feel more alert & perform better later in day/night
- irregular bedtime habits: higher propensity for insomnia
- experience less jet-lag
- tolerate shift work better
What is the biological clock - circadian rhythm?
- “clock-dependent alerting”
- clock genes: Period (per), Timeless (Tim), circadian locomotor output cycles kaput (CLOCK)
- variability influences differences in circadian rhythms
- thousands of genes expressed at once in most tissues & organs regulate cellular function
- vs. stimulation alerting: transitory, once removed will fall asleep
- one peak/strong alerting mid-morning & one mid-late afternoon
- biological clock ensures small sleep debt cannot overwhelm us
What is clock-dependent alerting?
physiological process that maintains & consolidates daytime wakefulness
What is hypocretin/orexin?
neuropeptide that regulates arousal, helps sustain alertness
- narcolepsy = orexin deficiency
What is sleep homeostasis?
- sleep time reduced, tendency to fall asleep when awake increases
- “extra” sleep obtained, tendency to fall asleep while awake decreases
- ability to stay awake influenced by interaction of clock-dependent alerting & homeostatic sleep drive
- best sleep: timing of biological clock & wake-sleep schedule in synchrony
What is sleep need?
“individual requirement of nightly amount of sleep that results in consistent optimal daytime alertness”
What is sleep tendency?
strength of inclination/impulse to fall asleep
What is sleep latency?
time it takes from bedtime to sleep onset (MSLT)
increase/strong sleep tendency = short/decreased sleep latency
greater accumulated sleep loss = stronger sleep tendency
What is the Multiple Sleep Latency Test (MSLT)?
- objective test to measure strength of daytime sleep tendency
- average time to fall asleep during day, if trying to do so in calm, quiet, monotonous environment, w/ no other distractions or disturbances
- 5 measurements: 9, 11am, 1, 3, 5pm
- each nap opportunity: 20 mins
- measure over 7-8 days:
- no substantial change = sleep obtained is amount needed
- daily mins increases = amount of sleep obtained increasing, closer to sleep need
- daily mins decreases = need more sleep than obtaining
What is the Maintenance of Wakefulness Test (MWT)?
- average time to sleep, if resisting sleep
- reclined in calm, quiet, monotonous, dark room
- 20-40mins, in 2hr intervals
- used by transportation as measure of post surgical/CPAP use
What are the consequences of habitual sleep deprivation? (p, acmecp, u)
progressive decline in:
- alertness & ability to maintain focus & attention - cognitive performance - mood - energy & motivation - control, coordination & impulsiveness - pain - underlying variable: strength of tendency of brain to sleep
What is the biological clock?
consists of controls & timing mechanisms that maintain daily 24hr oscillations
- interaction based on transcription-translation feedback loops of “clock genes” & their protein products
What is the opponent process model?
interaction of sleep homeostasis & clock-dependent alerting to produce sleep/wakefulness cycle
- correct timing of clock-dependent alerting
- avoiding accumulation of overly large sleep debt
What are the principles of optimal alertness?
- not the result of absent/v. low sleep debt, requires stimulation from clock/external sensory input or both
- napping at onset of midday dip in daytime alertness
What is sleepiness?
- 3 levels of alertness:
- energetic, motivated, active, peak alertness
- tired, lethargic, unmotivated
- drowsy, sleepy
- pleasant or unpleasant: if permitted to sleep & where
- difficulty communicating sleepiness: children under 9 yrs old + stigma w/ terms
- can’t judge arousal states well
- underestimate daily & long term impact of sleepiness
What is sleep debt?
accumulated amount of sleep lost than daily need
larger debt:
- stronger drive & tendency, short latency
- cognitive impairment, affective impact
- carry large debt: cannot obtain full “payback”
- obtain as much as possible one night
- continue to increase sleep subsequent nights or nap
What is the twilight zone of sleepiness?
- more than 50+ hrs sleep deprivation
- MSLT scores: 5 mins or less
What is the history of sleep deprivation?
Patrick & Gilbert (1896): 90 hrs
- lowered temp, slowed reaction time, memory + sensory decline
Randy Gardner (1965): 17 yr old, Guiness World Record 260 hrs
- fluctuating symptoms: blurred vision, memory decline, irritability, hallucinations, unable to sleep
- 4th day: EEG altered, “no longer awake”
- after: no adverse effects
What are findings from animal studies on sleep deprivation?
Rechtschaffen (1980’s) rat on rotating table, above water
- stop grooming, skin lesions
- lose weight despite increase in food intake, body temp declines, reduced thyroxin levels, large cortisol release
- lymph nodes fill with bacteria from intestine, immune system dysfunction, die within 2-3 weeks
What are factors that lead to sleep deprivation?
- use of screens
- “caffeine culture”: 8-14hrs to excretion
- “fit more in, get it done culture”, 24-hr availability, expectations of immediacy
- work schedules/type
- social events timing, priorities
- stress
- external stimuli
What are the physiological effects of sleep deprivation? (1)
- yawning
- slow eyelid closure, itchy eyes
- heart palpitations
- head drop w/ startle response
- tremors, muscle aches
- increased tendon reflexes & muscle spasm
- body temperature drop
- increased sensitivity to pain
What are the physiological effects of sleep deprivation? (2)
- decreased resistance to infection:
- decline in immune system
- natural killer cells unable to fight entering antigens & existing bacteria/viruses
- partial/total loss of effect of recent vaccinations
- growth hormone reduced
- longer recovery after exercise
- increase in cortisol release
What are the physiological effects of sleep deprivation? (3)
- decrease in leptin, increase in ghrelin & insulin secretion = more fat storage
- chronic sleep dep: high blood pressure, diabetes, obesity
- brain: more/varied brain regions “help out” in complex tasks
- caffeine helps arousal of brain, but functions dependent on prefrontal cortex remain impaired
- micro-sleeping
- REM rebound: REM pressure, takes longer than N3 rebound
What is micro-sleeping?
brief NREM sleep, complete inattention but denial of sleeping
What is REM rebound?
higher REM % when return to sleep
- antidepressants eliminate REM w/o effects
What is REM pressure?
pressure for REM to rebound as fast as possible, missing REM stage
What are the psychological effects of sleep deprivation? (1)
- psychomotor, cognitive & perceptual effects
- loss of alertness, reaction time
- lapse in concentration
- impaired ability on complex tasks
- innovation, creativity & flexibility decreases
- simple, well-practiced, externally motivated, less than 10 min less effected
- decrease in ST memory
- loss of verbal fluency
What are the psychological effects of sleep deprivation? (2)
- hesitancy in decision making/errors of inattention
- mistakes more frequent: if competing distractions & sorting involved
- inability to plan ahead
- risk taking behaviour, impulsivity increases
- increase chance of injury
- pessimism, impatience, irritability, anger, controlling negative mood, more susceptible to arguments
What are the psychological effects of sleep deprivation? (3)
- inappropriate behaviours, emotional outbursts
- unable to judge space/volume
- role clarity declines, personal focus increases
- unable to be empathetic
- more susceptible to suggestions
- disorientation, confusion
- mistrustful, paranoia, hallucinations
What are ways to stay awake during sleep deprivation?
- masking: extraneous influences override sleep propensity, temporary
- alcohol worsens sleepiness
- splashing cold water, fast moving air, loud music, dance around: temporarily reduce effects
- caffeine followed by nap can assist for up to 3 hrs
What are the societal effects of sleep deprivation? (1)
- sport performance: “home turf advantage” & speed, shot accuracy decreased
- parental information on sleep training & consequences of sleep deprivation limited
- school aged children misdiagnosed w/ behaviour disorders
- university students: depart for vacation
- misdiagnoses, medical errors
- severe, fatal motor vehicle injuries
What are the societal effects of sleep deprivation? (2)
- driving after 24hr sleep deprivation = 0.10 blood alcohol level (legally drunk)
- firefighters, police, military personnel
- physicians, nurses, paramedics, anesthesiologists, medivac
- taxi drivers, bus drivers, air traffic control & air mechanics
- emergency utility workers
- oil tankers, nuclear reactor management
What are things we can do to prevent sleep deprivation?
- close gap b/w medical scientific sleep knowledge & application: prevent deleterious effects/large catastrophes
- respect sleep, take responsibility for healthy sleep, restructure priorities, learn to manage it
- if sleep educated: talk w/ family & friends
- sleep specialists provide education for all levels
- reach leaders in academia, government + health and safety industries
What are consequences of sleep debt?
- impairs: mood, sense of well-being, energy, intellectual function, performance & attentiveness
- affects classroom behaviour & mood in children
- associated w/ suicide ideation & suicidal behaviour
- imbalances in brain regions w/ sleep disturbances associated w/ risk-taking behaviour
What is the optimal sleep/wake schedule?
- sleep debt reduced to as low as possible
2. maintain bedtime schedule that fulfills sleep requirement
What is full alertness?
absence of sleepiness and/or tiredness & optimisation of energy, motivation & intellectual capacity
What is the Stanford Sleepiness Scale (SSS)?
- measures subjective sleepiness
- statements that describe range of feeling states associated w/ 7 levels of sleepiness/alertness
- choose one that best describes, rating every hour
What is the Epworth Sleepiness Scale?
- obstructive sleep apnea & narcolepsy
- max = 24, excessive sleepiness = < 10
What are other causes of tiredness?
- decreased stimulation
- physical exertion
What are the waking functions affected by sleep?
- task performance impaired
- ability to do complex tasks impaired
- mood negatively affected
- motivation decreases: apathy
- self-control & impulsiveness decreases
- high-level cognitive function impaired, negatively affected: memory & creativity
- lapses & micro-sleeps increase
- psychomotor vigilance task: slower reaction time
- brain activity: function of specific brain areas diminish
What is apathy?
tendency to sit & do nothing
What is the psychomotor vigilance task?
- 10 mins, subject watches small screen for flashes of light
- press button quickly in reponse to each flash
What is “home turf advantage”?
team playing at time of peak circadian alerting
What is a sleep crisis?
- sudden, unexpected need to stay up all night for critical task/emergency
- “all nighter”
- worsening sleep disorder to point of serious illness/high risk to safety
What is an “all nighter”?
self-chosen willingness to stay awake for full nycthemeron
How can we cope with sleep crises?
- knowledge, preparation, use of tools
- know sleep need & bio rhythms, best time for perform
- biological clock at lowest ebb in middle of night: more prone to distraction, ST memory recall issues, slow RT, mistakes & cognitive issues
- attempt to plan ahead
- lower sleep debt previous to crises
- avoid alcohol, fatty/heavy foods
What are the types of naps?
- emergency nap
- preventative: prepare for sleep loss
- habitual
- selective, strategic: for performance
What are the best napping conditions & can napping do?
- time: 10-90mins, less than 4 hrs
- diurnal schedule: before 3-4pm
- improve objective performance
What is jet lag?
- mismatch of internal circadian clock w/ external local clock b/c of rapid travel
- timing offset: hunger, fatigue/energy, activities
- feel ill, flu-like: nausea, GI (gas intestinal) upset/constipation/diarrhea, muscle soreness, headaches
- distracted, disorientation, moody
- 1/3 not affected at all, others mild to debilitating
What makes jet lag worse?
- travelling east
- greater time zones
- older age
How does direction difference affect jet lag?
“east is the beast, west is the best”
- travelling east:
- body’s circadian rhythm behind local time
- problems falling asleep at local bedtime
- difficult to wake up in the morning
- v. few issues travelling north or south
What are ways to adjust to jet lag? (1)
- adjust body temp, hormonal rhythms
- complete recovery:
- to the west: 1 day per time zone
- to the east: 1.5 days per time zone
- rapid changes the first few days, tapering off
- try to “live in the time zone” the arrival clock before you leave, or make small adjustments 1 week to 1-2 days before
- sleeping pill
What are ways to adjust to jet lag ? (2)
- set/reset if lengthy stay
- attempt to “be local” when you arrive
- exposure to sunlight, bright light
- nap: only if necessary, 30min max, drop in clock dependent alerting
- melatonin:
- flying to later time = take earlier
- flying to earlier time = take late in the day
What are the types of shift work?
- day: 7/8am - 4/5pm
- evening/swing: 4pm - midnight, 6pm - 1am
- graveyard: 11/12pm - 6/8am
- split: 5/6am - 10am & 7 - 10/11pm
What are the challenges with shift work?
- shifts change regularly
- common: one week on/off
- daytime to graveyard phase shift most difficult
- more difficult for MT than ET, people who have a large sleep need, people over 50yrs old, or with chronic illness or sleep disorders
- tend to sleep less & less efficient if attempting to do so during the day
- difficult to live w/ others on diurnal schedule will switch during days off
What are the features of shift workers?
- less job satisfaction, more absent
- 50% higher than average MVA when driving home
- more negative moods, emotional issues, report social isolation family issues & +57% divorce rates
- higher reports of stomach & GI problems, CV disease, and cancer, higher mortality rates
What are ways to cope with shift work?
- consistent shifts: stay on day/night for 3+ weeks
- slow graduating clockwise shifts: day to evening, to night to day
- more light during shift & very dark situations for sleeping during the day
What is the goal of sleep hygiene?
- continuous, quality sleep, for optimal daytime alertness
- make sleep a priority over other choices
What is the best sleep environment?
- bedroom: associate room only w/ sleeping & sexuality
- quiet: earplugs, reduce unpredictable noise, music/TV, voices
- dark: window & eye coverings, avoid screens for reading, light emitting in room
- comfortable, clean bed
- control temp, air circulation & humidity: cooler w/ warm blankets/clothing
What are physical sleep practices?
- consistent sleep schedule: preparation, time of day/night; including weekends
- avoid working out/exercise 2-3hrs before, depending on type & time of day
- stay in bed, try to sleep when drowsy not if wide awake
What are psychological sleep practices?
- adequate time to unwind, calming pre-sleep routine before
- avoid looking at clock
- mental listing: paper, pen beside bed/do so before heading to bed/bedroom
- worry/anxious: self-talk, permission to sleep to deal w/ issue next day
How do substances affect sleep?
- avoid = caffeine post 4pm, alcohol, spicy, heavy/fatty or large meals, large amounts of fluid
- if hungry, warm drink; tryptophan
- be aware of when smoking/reduce: awake if nicotine levels reduce during night
- read medication inserts carefully, side effects & synergistic interactions
- valerian, chamomile, lemon balm, lavender, kava, cherry juice: no effect compared to placebo
How does THC affect sleep?
- low dose (4-20mg) = sedative, reduced REM, N3 increase with initial use
- high dose (50-210mg) = psychoactive effect, REM + N3 decrease
- stop use = REM rebound, increased sleep latency, reduced sleep efficiency
How does pain affect sleep?
sleep onset/latency affected, less N3, more awakenings
How does illness affect sleep?
bacterial, fungal, viral infections: increase sleepiness
- increase in cytokines -> N3 time & amount of delta waves produced 1-2 days following infection & then decrease below normal levels
- REM sleep decreased during infection
How does music affect sleep?
- soft melodic: enhance sleep onset
- unpredictable stimulating/annoying: affects onset & maintenance of sleep
How does weather affect sleep?
- weather extremes/climate change = need adaptation to changes
- lunar phase, solar disturbances, barometric pressure
How does driving affect sleep & how to prevent drowsiness?
- sleep debt causes drowsiness
- plan ahead: reduce sleep debt before trip + leave when circadian clock has you more alert
- several drivers
- if you feel drowsy, STOP DRIVING
- nap
- coffee after nap
What is “over-sleeping”?
sleeping for more than you believe you should/need
What are the effects of sleeping too much?
- extra sleep: low efficiency, very little N3
- feeling groggy/lethargic/“thick headed”, sore muscles, emotional low, irritability
- irrational, impulsive, socially embarrassing, no memory of activity
- typically 10-15min post long sleep/nap, up to an hour
What is sleep inertia?
- lack mobility for extended period
- wake-up when mid-day dip in clock dependent altering
- wake up during N3
- worse w/ sleep dep: sleep debt exists
- less noticeable following gradual morning awakening after full night of normal length & quality of sleep
- cannot “store sleep”: remain awake when enough
