Test your sleep science knowledge: learn how body clocks, sleep stages, and screen choices affect rest.

Q1. About how many repeating cycles of NREM and REM sleep does a typical night contain?
- One to two cycles
- About four to five cycles
- About eight to ten cycles
- More than twelve cycles
Answer: About four to five cycles — A typical night has roughly four to five repeating NREM–REM cycles.
Q2. NREM sleep moves from lighter sleep toward its deepest slow-wave stage. Which stage is the deepest?
- N1
- N2
- N3
- REM
Answer: N3 — N3 is the deepest NREM, or slow-wave, stage.
Q3. Which sleep stage is associated with rapid eye movements, vivid dreaming, and brain activity resembling wakefulness?
- N1
- N2
- N3
- REM
Answer: REM — REM includes rapid eye movements, vivid dreaming, and wake-like brain activity.
Q4. Which option describes a technology-based approach identified as potentially helpful for circadian-system function and sleep?
- Using blue-light-blocking glasses or screen-filtering apps
- Increasing bright screen exposure before bed
- Keeping all device notifications active overnight
- Replacing a regular sleep routine with unrestricted screen use
Answer: Using blue-light-blocking glasses or screen-filtering apps — Blue-light-blocking glasses or screen-filtering apps may help reduce evening light exposure and support circadian timing and sleep; they are not guaranteed to do so.
Q5. Why can bright evening light work against sleep?
- It can delay circadian rhythms and affect sleep timing
- It always causes immediate deep sleep
- It permanently eliminates REM sleep
- It guarantees earlier sleep onset
Answer: It can delay circadian rhythms and affect sleep timing — Bright evening light can delay circadian timing and shift sleep later.
Q6. How should guided meditation, sleep stories, behavioural prompts, and sleep-tracking tools generally be understood according to the research?
- As aids that may support relaxation and sleep routines
- As guaranteed replacements for broader behavioural treatment
- As causes of unavoidable circadian misalignment
- As methods that eliminate the need for consistent sleep timing
Answer: As aids that may support relaxation and sleep routines — Meditation, sleep stories, behavioural prompts, and tracking tools may support relaxation or sleep routines, but they are aids rather than guaranteed replacements for broader behavioural treatment.

Test your sleep science knowledge: learn how body clocks, sleep stages, and

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