Poor Sleep Hygiene Baseline
Late caffeine, bedtime screens, irregular schedules erode nightly sleep quality.
- 45: Baseline quality score (out of 100)
- 42 min: Sleep latency (time to fall asleep)
- 0 of 4: Behaviors adopted (no intervention yet)
- ~35%: Adults with poor sleep (report insufficient sleep)
Late caffeine intake
Afternoon caffeine blocks adenosine receptors well past bedtime.
Screens in bed
Blue light suppresses melatonin and delays sleep onset.
Irregular schedule
Shifting bed and wake times confuse the circadian clock.
Caffeine Cutoff Adopted
Stopping caffeine by early afternoon restores natural sleep pressure.
- ~5-6 hr: Caffeine half-life (lingers into evening)
- 2:00 PM: Cutoff time adopted (early-afternoon limit)
- ~15%: Latency improvement (by week two)
- 1 of 4: Behaviors adopted (caffeine only)
Adenosine and alertness
Caffeine blocks the chemical that signals sleepiness.
Cutoff timing
An early-afternoon cutoff clears caffeine before bedtime.
Early measurable gain
Sleep latency shortens within the first two weeks.
Screen Curfew Adopted
Cutting screens an hour before bed protects melatonin release.
- ~50%: Blue light suppression (melatonin reduction)
- 60 min: Curfew window (before lights out)
- ~30%: Latency improvement (combined with caffeine cutoff)
- 2 of 4: Behaviors adopted (caffeine + screens)
Melatonin suppression
Screen light signals daytime to the brain's clock.
One-hour buffer
A screen-free hour lets melatonin rise naturally.
Compounding effect
Two adopted behaviors improve quality faster than one.
Consistent Schedule Adopted
Fixed sleep and wake times, even weekends, stabilize circadian rhythm.
- <30 min: Schedule variance target (night to night)
- same time: Weekend consistency (no social jet lag)
- ~60%: Quality improvement (above baseline)
- 3 of 4: Behaviors adopted (plus consistent timing)
Circadian anchoring
A fixed wake time anchors the whole sleep cycle.
Social jet lag
Weekend shifts in bedtime undo weekday gains.
Three-behavior stack
Timing consistency compounds with caffeine and screen changes.
Cumulative Improvement
Four combined behaviors yield the largest measurable sleep-quality gain.
- ~92: Peak quality score (out of 100, week 8)
- ~9 min: Sleep latency (down from 42 min)
- 4 of 4: Behaviors adopted (full intervention)
- ~8 wk: Weeks to plateau (gains taper after)
Exercise timing
Daytime exercise, not near bedtime, deepens later sleep.
Compounding curve
Combined behaviors produce a steeper improvement slope.
Diminishing returns
Gains slow after eight weeks as quality approaches ceiling.