Difficulty: Mixed
What are the two main sleep phases?
A NREM and REM
B Light and awake
C Dreaming and waking
D Deep and quiet
Answer: A. NREM and REM Sleep cycles through non-REM (NREM) and rapid eye movement (REM) phases.
How many stages does non-REM sleep have?
A One stage
B Three stages
C Two stages
D Five stages
Answer: B. Three stages NHLBI describes three stages of non-REM sleep.
What happens during NREM stage 1?
A Deep sleep begins
B REM dreaming starts
C Wakefulness transitions to sleep
D The person is fully awake
Answer: C. Wakefulness transitions to sleep Stage 1 is the transition between wakefulness and sleep.
During which NREM stage is a person asleep?
A Stage 1 only
B Stage 3 only
C REM only
D Stage 2
Answer: D. Stage 2 NHLBI notes that a person is asleep by stage 2.
Which NREM stage is called deep sleep?
A Stage 3
B Stage 1
C Stage 2
D REM
Answer: A. Stage 3 Stage 3 is also called deep or slow-wave sleep.
What pattern defines slow-wave sleep?
A A dream story
B A measured brain-wave pattern
C A breathing position
D A fixed heartbeat
Answer: B. A measured brain-wave pattern Stage 3 is named for a particular brain-activity pattern measured during sleep studies.
When do people usually spend more time in NREM stage 3?
A Only at sunrise
B Only after waking
C Early in the night
D Late afternoon
Answer: C. Early in the night People usually spend more time in stage 3 early in the night.
What is commonly active during REM sleep?
A Only the muscles
B The digestive system only
C No brain activity
D The brain and eyes
Answer: D. The brain and eyes During REM sleep, brain activity is high and the eyes twitch.
How does REM brain activity compare with waking activity?
A It can look similar
B It stops completely
C It always slows to zero
D It matches deep sleep
Answer: A. It can look similar Brain activity measured during REM can be similar to activity during wakefulness.
When does dreaming usually happen?
A Only in stage 1
B During REM sleep
C Only while awake
D Only during naps
Answer: B. During REM sleep Dreaming usually happens during REM sleep, though it is not limited to that phase.
Why do muscles normally become limp during REM?
A To stop all breathing
B To prevent eye movement
C To limit dream enactment
D To increase body heat
Answer: C. To limit dream enactment Muscles normally become limp during REM to help prevent people from acting out dreams.
When is REM sleep usually more common?
A Only at bedtime
B Only after naps
C Early evening only
D Later in the night
Answer: D. Later in the night People usually have more REM sleep later in the night.
How long does a sleep cycle often last?
A About 80 to 100 minutes
B Exactly 30 minutes
C Exactly two hours
D Five to ten minutes
Answer: A. About 80 to 100 minutes NHLBI says sleep cycles typically restart every 80 to 100 minutes.
How many sleep cycles usually occur in one night?
A One cycle
B Four to six cycles
C Ten to twelve cycles
D Two cycles
Answer: B. Four to six cycles Most people usually experience four to six cycles during a night.
Can a sleep cycle last exactly 90 minutes every time?
A Yes, always
B Only for adults
C No, cycle lengths vary
D Only during REM
Answer: C. No, cycle lengths vary The 80-to-100-minute range shows that cycle length varies.
What may happen briefly between sleep cycles?
A Permanent wakefulness
B A new day begins
C Deep sleep ends forever
D A short awakening
Answer: D. A short awakening People may wake briefly between sleep cycles.
Which sensors can sleep studies use to classify stages?
A Eye and brain signals
B Footstep counters only
C Phone screen time
D Room temperature only
Answer: A. Eye and brain signals Sleep studies can record eye movements and brain activity to classify phases and stages.
What is polysomnography commonly used to study?
A Daily food choices
B Sleep patterns and stages
C Exercise speed
D Social-media use
Answer: B. Sleep patterns and stages Polysomnography records signals such as brain activity, eye movements, and other body functions during sleep.
Does every dream occur during REM sleep?
A Yes, only REM
B Only during stage 3
C No, dreams can occur otherwise
D Only while awake
Answer: C. No, dreams can occur otherwise Dreaming usually occurs during REM, but dreams can also happen during other sleep stages.
Why is NREM called non-REM sleep?
A It occurs only awake
B It contains no brain activity
C It has no stages
D It is distinct from REM
Answer: D. It is distinct from REM NREM is the sleep phase distinct from rapid eye movement sleep.
What happens to eye movement during REM?
A The eyes twitch
B The eyes stop moving forever
C Only one eye opens
D The eyes track sound
Answer: A. The eyes twitch Rapid eye movements occur during the REM phase.
Which stage marks the earliest transition into sleep?
A NREM stage 3
B NREM stage 1
C REM
D NREM stage 2
Answer: B. NREM stage 1 NREM stage 1 is the transition from wakefulness into sleep.
Why is stage 2 important to recognize?
A It is the waking stage
B Another name for REM
C It marks established sleep
D It happens only at dawn
Answer: C. It marks established sleep NHLBI describes stage 2 as the point when a person is asleep.
What does stage 3 sleep often become called?
A Rapid eye sleep
B Light transition
C Morning sleep
D Slow-wave sleep
Answer: D. Slow-wave sleep Stage 3 is known as deep sleep or slow-wave sleep.
How does slow-wave sleep typically change with age?
A It decreases through adulthood
B It increases forever
C It stays identical
D It disappears in childhood
Answer: A. It decreases through adulthood Slow-wave sleep peaks in early childhood and generally decreases through adulthood.
Which age group tends to spend more time in REM sleep?
A Older adults
B Newborns
C All adults equally
D Only teenagers
Answer: B. Newborns Newborns spend more time in REM sleep than adults.
When does slow-wave sleep peak in development?
A Late adulthood
B At birth only
C Early childhood
D During adolescence
Answer: C. Early childhood NHLBI reports that slow-wave sleep peaks in early childhood.
What happens to slow-wave sleep in teenage years?
A It rises sharply
B It stays fixed
C It becomes REM
D It drops from childhood levels
Answer: D. It drops from childhood levels Slow-wave sleep drops sharply during the teenage years and continues to decline through adulthood.
May older adults have very little slow-wave sleep?
A Yes, patterns change with age
B No, stages never change
C Only after naps
D Only during illness
Answer: A. Yes, patterns change with age Sleep patterns change with age, and older adults may have little or no slow-wave sleep.
Which sleep pattern can be normal between cycles?
A Staying awake all night
B Briefly waking
C Never entering REM
D Repeating stage 1 only
Answer: B. Briefly waking Brief awakenings can occur between normal sleep cycles.
What does sleep architecture describe?
A The bedroom layout
B A sleep schedule
C The structure of sleep stages
D A dream journal
Answer: C. The structure of sleep stages Sleep architecture refers to how sleep stages are organized and cycle through the night.
Can every night’s sleep architecture be identical?
A Yes, exactly
B Only in children
C Only without dreams
D No, patterns may vary
Answer: D. No, patterns may vary Sleep patterns can vary from night to night and across age groups.
Which stage usually increases later in the night?
A REM sleep
B NREM stage 3
C Stage 1 only
D Wakefulness only
Answer: A. REM sleep REM periods generally become longer or more frequent later in the night.
What may happen to deep sleep early in the night?
A No stage 3 occurs
B More time in stage 3
C REM replaces all sleep
D Wake time rises
Answer: B. More time in stage 3 People usually spend more time in stage 3 early in the night.
Why should exact cycle-timing claims be treated cautiously?
A Everyone has identical cycles
B Stages never change
C Cycle lengths naturally vary
D Clocks control REM
Answer: C. Cycle lengths naturally vary Sleep cycles vary in length, so exact 90-minute scheduling claims are oversimplified.
Can a phone app directly measure brain waves like a sleep study?
A Yes, every app can
B Only without sensors
C It measures dreams
D No, it estimates sleep patterns
Answer: D. No, it estimates sleep patterns Consumer apps may estimate sleep, but they do not directly record brain activity like a sleep study.
What can a clinical sleep study record besides brain activity?
A Eye movements and body signals
B Only spoken dreams
C Only room light
D Phone notifications
Answer: A. Eye movements and body signals Polysomnography can record eye movements, muscle activity, breathing, and other signals.
Which statement about REM muscle tone is accurate?
A All muscles contract strongly
B Muscles are normally very relaxed
C The body cannot breathe
D The eyes stop twitching
Answer: B. Muscles are normally very relaxed During REM, muscles normally become limp, although breathing and eye movements continue.
What does the word ‘rapid’ in REM refer to?
A Rapid breathing
B Rapid dreaming
C Rapid eye movements
D Rapid waking
Answer: C. Rapid eye movements REM stands for rapid eye movement.
Do NREM stages include only light sleep?
A Yes, all are light
B Only REM is sleep
C Stage 2 is waking
D No, stage 3 is deep
Answer: D. No, stage 3 is deep NREM includes lighter stages and stage 3 deep sleep.
What helps researchers identify sleep stages?
A Measured physiological signals
B Dream interpretation alone
C A person’s guess
D Bedtime only
Answer: A. Measured physiological signals Researchers classify sleep stages using measured signals, including brain activity and eye movements.
Can a dream report identify a sleep stage reliably?
A Yes, always
B No, stage measurement uses signals
C Only for children
D Only during naps
Answer: B. No, stage measurement uses signals Dream reports alone do not classify sleep stages; sleep studies measure physiological signals.
Why might sleep-stage proportions differ between people?
A Stages are fixed for everyone
B Only room color matters
C Age and sleep patterns differ
D Dreams set the stages
Answer: C. Age and sleep patterns differ Sleep patterns change with age and can vary between people.
What is a reasonable response to brief awakenings?
A They always mean illness
B They prove insomnia
C They stop all sleep
D They can occur normally
Answer: D. They can occur normally Brief waking between cycles can be normal.
Should someone schedule an alarm using a fixed 90-minute cycle rule?
A Not as an exact rule
B Yes, it works for everyone
C Only for REM
D Always at 90 minutes
Answer: A. Not as an exact rule Sleep cycles vary, so fixed 90-minute alarm rules are not reliable for everyone.
Which statement about deep sleep and age is accurate?
A It increases every decade
B It generally declines with age
C It is absent in infants
D It never changes
Answer: B. It generally declines with age Slow-wave sleep peaks early in life and generally declines through adulthood.
Can sleep stages be assessed from brain waves alone in research?
A Dream stories are enough
B Room light is enough
C Brain signals help classify stages
D A clock determines stages
Answer: C. Brain signals help classify stages Brain activity is one key signal used to classify sleep stages.
Which sequence correctly names the NREM stages?
A Stages A, B, and C
B Stages 2, 4, and 5
C Stages REM, N1, N2
D Stages 1, 2, and 3
Answer: D. Stages 1, 2, and 3 Modern sleep staging describes three NREM stages: stages 1, 2, and 3.
What is one key takeaway about sleep cycles?
A They repeat but can vary
B They last exactly 90 minutes
C They contain REM only
D They are identical across ages
Answer: A. They repeat but can vary Sleep cycles repeat through the night, but their length and stage patterns can vary.
When might someone briefly wake during a sleep cycle?
A Only after waking fully
B Between sleep cycles
C At bedtime only
D Only during deep sleep
Answer: B. Between sleep cycles Brief awakenings can occur between sleep cycles.