Frameworks · Body · 187

Light in the morning, dark at night

Teen clocks drift late. It's biology, not laziness.

SPWe reviewed the research on it.Sleep and recovery

Hand-drawn diagram of framework 187, Light in the morning, dark at night: Teen clocks drift late. It's biology, not laziness.
Framework 187 · in one look
How to use it
  1. Anchor the wake time.
  2. 20–30+ minutes of outdoor light within an hour of waking. Longer on grey winter mornings.
  3. Dim the last 1–2 hours. If scrolling is what pushes bedtime later, charge the phone away from the bed.
  4. No late weekend nights: they cancel the morning light.
How sure we are

S Evidence: strong. Large trials or many studies, pointing the same way.

P Evidence: promising. Good studies, but small or few. Use it and keep checking.

Sources

Crowley et al. 2018 (teen clocks run late: biology, not laziness) · Misiunaite et al. 2020 · screen studies are small and mixed.

Not medical, legal or financial advice.

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177 SCaffeine: capped, early, saved for the day that countsMy pre-workout is eight hours of sleep.132 SSleep your own numberNot a generic 7–9. Yours.128 PTrain with people, not just near themAt least one session a week together. Linked to longer lives.84 SPSame time every nightFix the wake time. Everything else follows it.298 SPGet up every 30Break the sitting every 30 minutes.69 PEight is the floor for teen athletesFor teen athletes, 8 hours is the minimum, not the goal.