Title: Sleep Science — LearnCoachAssist

Q: What is sleep?
A: A reversible, naturally recurring state of reduced responsiveness and altered consciousness.

Q: What are the two main types of sleep?
A: REM (rapid eye movement) and NREM (non-REM).

Q: What are the stages of NREM sleep?
A: N1 (light), N2 (deeper), N3 (deep/slow-wave).

Q: What is N1 sleep?
A: The lightest stage; transition from wakefulness; brief.

Q: What is N2 sleep?
A: Light sleep with sleep spindles and K-complexes; ~45-55% of total sleep.

Q: What is N3 sleep?
A: Deep slow-wave sleep; most physically restorative.

Q: What is REM sleep?
A: A stage with eye movements, vivid dreams, muscle paralysis, and brain activity similar to wakefulness.

Q: What is paradoxical sleep?
A: Another name for REM; brain is active but body is paralyzed.

Q: What is atonia (REM)?
A: Temporary muscle paralysis during REM, preventing acting out dreams.

Q: What is a sleep cycle?
A: One full progression through NREM and REM, ~90 minutes.

Q: How many sleep cycles per night?
A: 4-6 typically for an adult.

Q: How does sleep architecture change overnight?
A: Early cycles have more deep sleep; later cycles have more REM.

Q: What is sleep architecture?
A: The structure and pattern of sleep stages across a night.

Q: How much sleep do adults need?
A: 7-9 hours per night for most.

Q: How much sleep do teenagers need?
A: 8-10 hours.

Q: How much sleep do school-age children need?
A: 9-11 hours.

Q: How much sleep do toddlers need?
A: 11-14 hours, including naps.

Q: How much sleep do infants need?
A: 14-17 hours.

Q: How much sleep do seniors need?
A: 7-8 hours; quality may decline with age.

Q: What is the circadian rhythm?
A: The body's ~24-hour internal clock.

Q: Where is the master clock located?
A: The suprachiasmatic nucleus (SCN) in the hypothalamus.

Q: What is melatonin?
A: A hormone signaling darkness; promotes sleep.

Q: Where is melatonin produced?
A: The pineal gland.

Q: What suppresses melatonin?
A: Bright light, especially blue light.

Q: What is cortisol's role in sleep?
A: Cortisol naturally rises before waking; chronic stress disrupts sleep.

Q: What is adenosine?
A: A neurotransmitter accumulating during wakefulness; promotes sleep pressure.

Q: How does caffeine work?
A: Blocks adenosine receptors, reducing perceived sleepiness.

Q: What is the half-life of caffeine?
A: ~5-6 hours; varies by individual.

Q: When should you stop drinking caffeine?
A: 8-10 hours before bed for many; varies.

Q: What is sleep pressure?
A: Drive to sleep that builds with wakefulness.

Q: What are the two-process model components?
A: Process S (sleep pressure) and Process C (circadian rhythm).

Q: What is sleep debt?
A: Cumulative lack of sleep; partially recoverable.

Q: Can you fully repay sleep debt on weekends?
A: Partially; weekday deficits accumulate health costs.

Q: What is "social jet lag"?
A: Discrepancy between weekday and weekend sleep schedules.

Q: What is true jet lag?
A: Misalignment between internal clock and external time zone.

Q: What helps with jet lag?
A: Light exposure timing, melatonin, gradual schedule shifts.

Q: What is shift work disorder?
A: Sleep problems from working against the body clock.

Q: What are chronotypes?
A: Individual preferences for timing of sleep (morning lark, night owl).

Q: What percentage of people are night owls?
A: Roughly 20-25%; about 25-40% morning types; rest in-between.

Q: What is the role of genetics in chronotype?
A: Significant; clock genes like PER and CRY influence timing.

Q: What is sleep efficiency?
A: Time asleep divided by time in bed; ideally 85%+.

Q: What is sleep onset latency?
A: Time to fall asleep; normal is 10-20 minutes.

Q: What is sleep maintenance?
A: The ability to stay asleep through the night.

Q: What is WASO?
A: Wake After Sleep Onset — total wake time during the night.

Q: What is the recommended bedroom temperature?
A: 60-67°F (15.6-19.4°C) for most.

Q: Why does cool help sleep?
A: Body temperature drops naturally for sleep; cool room aids this.

Q: What is the role of darkness?
A: Supports melatonin production and undisturbed sleep.

Q: What is the role of quiet?
A: Reduces awakenings and arousals.

Q: What is the impact of light at night?
A: Suppresses melatonin and delays sleep onset.

Q: What is blue light?
A: Short-wavelength visible light; especially suppressive of melatonin.

Q: What devices emit blue light?
A: Phones, tablets, TVs, LED lights.

Q: What is the recommendation for screens before bed?
A: Avoid for 1-2 hours, or use night/blue-light filter.

Q: What is sleep hygiene?
A: Behaviors and environment supporting good sleep.

Q: What are key sleep hygiene practices?
A: Consistent schedule, cool dark quiet room, limit caffeine/alcohol, no screens before bed.

Q: What is the impact of alcohol on sleep?
A: Disrupts REM and fragments sleep despite initial sedation.

Q: What is the impact of nicotine on sleep?
A: A stimulant; harms sleep onset and quality.

Q: What is the impact of exercise on sleep?
A: Generally improves sleep; intense workouts late may interfere for some.

Q: What is the best time to exercise for sleep?
A: Morning or afternoon usually; individual variation.

Q: What is the impact of meals before bed?
A: Heavy or spicy meals can disrupt sleep; light snacks may help.

Q: What is the impact of hydration on sleep?
A: Adequate hydration helps; too much liquid causes nocturia.

Q: What is nocturia?
A: Waking at night to urinate.

Q: What is sleep apnea?
A: Repeated breathing pauses during sleep.

Q: What is obstructive sleep apnea (OSA)?
A: Airway blocks during sleep; most common type.

Q: What is central sleep apnea?
A: Brain fails to signal breathing muscles.

Q: What are symptoms of sleep apnea?
A: Loud snoring, gasping, daytime sleepiness, morning headaches.

Q: What is the gold standard treatment for OSA?
A: CPAP — continuous positive airway pressure.

Q: What is CPAP?
A: A device delivering pressurized air via mask to keep airway open.

Q: What is BiPAP?
A: Bilevel positive airway pressure for more complex cases.

Q: What is the AHI?
A: Apnea-Hypopnea Index — breathing events per hour.

Q: What AHI defines mild/moderate/severe OSA?
A: 5-15 mild, 15-30 moderate, 30+ severe.

Q: What is a sleep study (polysomnography)?
A: Overnight test recording brain, breathing, heart, movement.

Q: What is home sleep testing?
A: A simpler test focused on breathing; misses some conditions.

Q: What is insomnia?
A: Difficulty falling asleep, staying asleep, or non-restorative sleep.

Q: What is acute vs chronic insomnia?
A: Acute: short-term, often situational; chronic: 3+ nights/week for 3+ months.

Q: What is the prevalence of insomnia?
A: About 10% have chronic insomnia; 30%+ experience symptoms.

Q: What is the first-line treatment for chronic insomnia?
A: CBT-I (Cognitive Behavioral Therapy for Insomnia).

Q: What is CBT-I?
A: A structured therapy addressing thoughts and behaviors around sleep.

Q: What is sleep restriction therapy?
A: Temporarily limiting time in bed to consolidate sleep.

Q: What is stimulus control?
A: Re-associating bed with sleep through specific behaviors.

Q: What is sleep efficiency restriction example?
A: Spend in bed only the average time asleep; expand gradually.

Q: What is the "20-minute rule"?
A: If you can't sleep in 20 min, get up; return when sleepy.

Q: What is the role of consistent wake time?
A: Anchors circadian rhythm; more important than bedtime.

Q: What is the role of morning light?
A: Sets circadian clock; 10-30 minutes within an hour of waking.

Q: What is the role of darkness in the evening?
A: Supports melatonin rise and sleep onset.

Q: What is sleepiness vs fatigue?
A: Sleepiness is need to sleep; fatigue is lack of energy.

Q: What is daytime sleepiness?
A: Excessive drowsiness during waking hours; often a symptom of poor sleep.

Q: What is the Epworth Sleepiness Scale?
A: A questionnaire estimating daytime sleepiness.

Q: What is microsleep?
A: Brief involuntary episodes of sleep during wakefulness, especially when sleep deprived.

Q: What is sleep inertia?
A: Grogginess upon waking from deep sleep.

Q: What is the duration of sleep inertia?
A: Typically 15-30 minutes, longer if from deep sleep.

Q: What is restless legs syndrome (RLS)?
A: Urge to move legs, especially at night; can disrupt sleep.

Q: What is periodic limb movement disorder (PLMD)?
A: Repetitive limb movements during sleep.

Q: What is narcolepsy?
A: A neurological disorder of excessive daytime sleepiness and disrupted REM regulation.

Q: What is cataplexy?
A: Sudden muscle weakness triggered by emotion; symptom of narcolepsy type 1.

Q: What is the role of orexin (hypocretin)?
A: A wakefulness-promoting neurotransmitter; deficient in narcolepsy.

Q: What is REM sleep behavior disorder (RBD)?
A: Acting out dreams due to lost REM atonia.

Q: What is the link between RBD and Parkinson's?
A: RBD often precedes Parkinson's and related synucleinopathies.

Q: What is parasomnia?
A: Unusual behavior during sleep (sleepwalking, sleep talking, night terrors).

Q: What is sleepwalking?
A: Walking or complex behavior during deep NREM sleep.

Q: What are night terrors?
A: Episodes of intense fear during NREM; usually no memory.

Q: What is the difference between nightmares and night terrors?
A: Nightmares occur in REM and are remembered; terrors in NREM and not remembered.

Q: What is sleep paralysis?
A: Temporary inability to move when transitioning between sleep and wakefulness.

Q: What is hypnagogic state?
A: Transition into sleep; sometimes vivid imagery.

Q: What is hypnopompic state?
A: Transition out of sleep; also can have imagery.

Q: What is a sleep diary?
A: A daily log of sleep times, quality, and habits.

Q: What is actigraphy?
A: Movement-based tracking of sleep, often via wrist device.

Q: What are sleep trackers' limitations?
A: They estimate stages indirectly; accuracy varies.

Q: What is the role of consistency?
A: More important than total hours for circadian health.

Q: What is the impact of weekend "catch-up sleep"?
A: May help acutely but doesn't fully restore chronic deprivation.

Q: What is the relationship between sleep and immunity?
A: Sleep supports immune function; deprivation weakens it.

Q: What is the relationship between sleep and metabolism?
A: Poor sleep increases insulin resistance and hunger hormones.

Q: What is leptin?
A: A satiety hormone; reduced by sleep loss.

Q: What is ghrelin?
A: A hunger hormone; increased by sleep loss.

Q: What is the link between sleep and weight?
A: Sleep loss promotes weight gain via hormonal and behavioral changes.

Q: What is the relationship between sleep and cardiovascular health?
A: Insufficient sleep raises blood pressure and cardiovascular risk.

Q: What is the relationship between sleep and mental health?
A: Sleep loss worsens mood and anxiety; mental health affects sleep.

Q: What is the link between sleep and depression?
A: Bidirectional; insomnia is a risk factor and symptom.

Q: What is the link between sleep and cognition?
A: Sleep is essential for memory consolidation, learning, and decision-making.

Q: What is memory consolidation?
A: The process of stabilizing memories, primarily during sleep.

Q: What is declarative memory consolidation?
A: Facts and events; supported by NREM, especially slow-wave sleep.

Q: What is procedural memory consolidation?
A: Motor skills; supported by REM and sleep generally.

Q: What is the role of dreams?
A: Debated; theories include emotional regulation, memory processing, simulation.

Q: What is the activation-synthesis hypothesis?
A: Dreams are the brain making sense of random REM activity.

Q: What is the threat simulation theory?
A: Dreams rehearse responses to threats.

Q: What is the continual-activation theory?
A: Dreams maintain neural circuits during sleep.

Q: What is lucid dreaming?
A: Being aware you're dreaming while in the dream.

Q: What is reality testing (lucid dreaming)?
A: Habit of checking if you're awake; can carry into dreams.

Q: What is dream journaling?
A: Writing dreams immediately upon waking; improves recall.

Q: What is the impact of trauma on sleep?
A: PTSD often disrupts sleep and increases nightmares.

Q: What is imagery rehearsal therapy?
A: A treatment for nightmares involving rewriting dreams.

Q: What is sleep deprivation?
A: Insufficient sleep over time, affecting all body systems.

Q: What are effects of one night without sleep?
A: Impaired cognition, mood disturbance, slower reactions; similar to alcohol intoxication.

Q: What are effects of chronic sleep deprivation?
A: Increased disease risk: heart, diabetes, dementia, cancer; mood issues.

Q: What is the link between sleep and Alzheimer's?
A: Sleep helps clear amyloid-beta; chronic deprivation may increase risk.

Q: What is the glymphatic system?
A: The brain's waste-clearance system; most active during sleep.

Q: What is the role of slow-wave sleep in brain cleaning?
A: Cerebrospinal fluid flow increases during deep sleep, clearing toxins.

Q: What is the relationship between sleep and longevity?
A: Both too little and too much sleep associate with higher mortality.

Q: What's the "sweet spot" of sleep duration?
A: 7-8 hours for most adults; varies individually.

Q: What is napping?
A: Short daytime sleep; can boost alertness if timed well.

Q: What is the ideal nap length?
A: 10-20 minutes to avoid sleep inertia; or 90 minutes for full cycle.

Q: What is the power nap?
A: A short nap (10-20 min) for alertness without deep sleep.

Q: What is the caffeine nap?
A: Coffee then 20-min nap; caffeine kicks in upon waking.

Q: What is napping's impact on nighttime sleep?
A: Long or late naps can hurt night sleep.

Q: What is sleep medication?
A: Short-term aid for some; not first-line for chronic insomnia.

Q: What are common prescription sleep medications?
A: Zolpidem (Ambien), eszopiclone (Lunesta), suvorexant (Belsomra), trazodone.

Q: What are common OTC sleep aids?
A: Diphenhydramine (Benadryl), doxylamine, melatonin.

Q: What is the issue with diphenhydramine?
A: Anticholinergic; linked to cognitive issues with chronic use.

Q: What is the role of melatonin supplements?
A: Useful for jet lag and circadian shifts; less effective for sleep onset alone.

Q: What is the typical melatonin dose?
A: 0.3-3 mg for most purposes; lower often better.

Q: What is the timing of melatonin?
A: 2-3 hours before desired sleep time for circadian effects.

Q: What is the role of valerian?
A: Herbal remedy; modest evidence; varies in quality.

Q: What is the role of magnesium?
A: May aid sleep, especially with deficiency.

Q: What is the role of L-theanine?
A: An amino acid promoting calm; mild sleep benefits.

Q: What is the role of CBD?
A: Mixed evidence for sleep; long-term effects unclear.

Q: What is the impact of cannabis on sleep?
A: Suppresses REM; tolerance develops; mixed picture.

Q: What is the relationship between alcohol and REM?
A: Alcohol suppresses REM; rebound after stopping.

Q: What is the impact of caffeine on sleep architecture?
A: Reduces deep sleep and total sleep time.

Q: What is the role of bedroom design?
A: Cool, dark, quiet, comfortable mattress and bedding.

Q: What is the role of mattress?
A: Should provide support and comfort; varies by individual.

Q: What is the typical mattress lifespan?
A: 7-10 years.

Q: What is the role of pillow?
A: Supports neck alignment; varies by sleep position.

Q: What is back vs side vs stomach sleeping?
A: Side is most common and often easier on back/airway; stomach is hardest on the spine.

Q: What is the impact of pets in bed?
A: Mixed; some find comforting, others see disrupted sleep.

Q: What is the impact of a partner?
A: Sleep can be disturbed by movement, snoring, schedule; some couples use separate beds ("sleep divorce").

Q: What is sleep divorce?
A: Couples sleeping separately for better rest; gaining acceptance.

Q: What is the impact of pregnancy on sleep?
A: Many disruptions: discomfort, hormones, frequent urination.

Q: What is the impact of menopause on sleep?
A: Hot flashes and hormone shifts disrupt sleep.

Q: What is the impact of aging on sleep?
A: Lighter sleep, more awakenings, earlier wake times.

Q: What is the role of consistency in pediatric sleep?
A: Routine and timing strongly affect children's sleep.

Q: What is the recommended bedtime for school-age kids?
A: 8-10 hours before wake time; varies by age.

Q: What is the role of screens in adolescent sleep?
A: Major disruptor; delays bedtime, suppresses melatonin.

Q: What is the typical teen circadian shift?
A: Phase delay; teens naturally sleep later.

Q: What is the relationship between school start times and adolescent sleep?
A: Earlier starts increase sleep deprivation; later starts improve outcomes.

Q: What is the impact of mental load on sleep?
A: Worry and rumination disrupt sleep onset and maintenance.

Q: What is "worry time"?
A: Scheduled time earlier in the day for processing concerns.

Q: What is "brain dump" before bed?
A: Writing tasks/thoughts to clear mind.

Q: What is the relaxation response?
A: Deliberate calming through breath, imagery, body scan.

Q: What is progressive muscle relaxation?
A: Tensing and releasing muscle groups for relaxation.

Q: What is the role of meditation?
A: Regular practice can improve sleep quality.

Q: What is breathwork for sleep?
A: Slow, deep breaths activate parasympathetic system.

Q: What is the 4-7-8 breathing technique?
A: Inhale 4, hold 7, exhale 8; calming breath pattern.

Q: What is the role of body scans?
A: Mindfully attending to body sensations; calming.

Q: What is the role of journaling?
A: Helps process stress before bed.

Q: What is the role of cold showers for sleep?
A: Some find warm-then-cool drop aids sleep; effects vary.

Q: What is the role of warm baths before bed?
A: A bath ~90 min before bed cools the body subsequently, aiding sleep.

Q: What is the right environment for shift workers?
A: Blackout curtains, white noise, consistent sleep schedule.

Q: What is sleep banking?
A: Sleeping extra before anticipated sleep loss.

Q: What are NSDR practices?
A: Non-Sleep Deep Rest; yoga nidra and similar protocols for restoration.

Q: What is yoga nidra?
A: A guided relaxation practice mimicking sleep.

Q: What is the role of cool air vs warm bedding?
A: Cool ambient + warm covering creates optimal sleep environment for many.

Q: What is the importance of routine?
A: Predictable signals to the body when it's time to sleep.

Q: What is "sleep efficiency stacking"?
A: Combining good practices for compounded benefit.

Q: What is the relationship between exercise type and sleep?
A: Aerobic and resistance both help; intensity timing matters individually.

Q: What is the role of sunlight overall?
A: Day sunlight strengthens circadian signal for night sleep.

Q: What is the role of regular meal timing?
A: Supports circadian alignment.

Q: What is the impact of fasting on sleep?
A: Time-restricted eating can improve sleep for some.

Q: What is the role of late-night eating?
A: Often delays sleep and reduces quality.

Q: What is "trying too hard to sleep" problem?
A: Effortful pursuit of sleep often backfires; paradoxical intention helps.

Q: What is paradoxical intention?
A: Try to stay awake; can reduce performance anxiety around sleep.

Q: What is sleep effort?
A: Conscious striving to sleep; counterproductive.

Q: What is "let go" attitude?
A: Accepting wakefulness without distress; often allows sleep to come.

Q: What is the takeaway of sleep science?
A: Sleep is a pillar of health; protect it with consistent timing, environment, and habits.