Module 13

Circadian Rhythm Optimization Checklist

Sleep timing, meal timing, activity timing — align your family's biology with the sun

Your child's body runs on a 24-hour clock that governs hormone release, digestion, immune function, memory consolidation, and tissue repair. When daily routines align with that clock, everything works better. When they don't — late meals, erratic bedtimes, bright screens at night — the system fights itself. This checklist covers the three pillars of circadian alignment: light, food, and activity.

Morning Routine (The Circadian Anchor)

Wake at a consistent time (within 30 minutes, including weekends)— The single most important circadian anchor. Consistency beats duration.

Get outdoor light within 30 minutes of waking— 10-20 minutes of outdoor light, even on cloudy days. Sunglasses off.

Eat breakfast within 1 hour of waking— Food is a secondary circadian timer (peripheral clock). Include protein and fat.

Include physical movement in the morning— Even 5-10 minutes of active play, stretching, or a walk. Movement signals 'daytime' to the body.

Avoid screens for the first 30-60 minutes after waking— Let natural light and real-world input set the circadian tone before introducing artificial stimulation.

Daytime Habits

Outdoor time totals 1-2 hours per day— Split across morning and afternoon is fine. This also protects against myopia.

Meals happen at roughly the same times daily— Breakfast, lunch, and dinner within a 1-hour window day to day. Peripheral clocks in the gut sync to meal timing.

Naps (if age-appropriate) end by 3:00 PM— Late naps push bedtime later and fragment nighttime sleep. Exception: infants under 6 months.

Physical activity happens before 5:00 PM— Vigorous exercise close to bedtime raises core body temperature and delays sleep onset.

Caffeine (for parents) stops by noon— Caffeine has a half-life of 5-6 hours. A 2 PM coffee means half the caffeine is still active at 8 PM.

Evening Wind-Down (The Critical 2 Hours)

Dinner finishes 2-3 hours before bedtime— Eating close to sleep disrupts melatonin and growth hormone release. Light snack is OK if needed.

Screens off 1.5-2 hours before bedtime— This is non-negotiable for children. Blue light at close range suppresses melatonin for 60-90 minutes.

Overhead lights off — switch to warm lamps— After dinner, use 2700K or lower lighting. Salt lamps, candles, and amber bulbs are ideal.

Bath or shower 60-90 minutes before bed— Warm water raises skin temperature, then the cool-down afterward triggers drowsiness (thermoregulation effect).

Consistent bedtime routine (15-30 minutes)— Same order, same activities, same cues every night. The routine itself becomes a sleep signal.

Bedroom is cool (65-68°F / 18-20°C), dark, and quiet— Core body temperature needs to drop 1-2°F for sleep onset. Cool room facilitates this.

No food or milk in bed (for children old enough)— Eating in bed creates an association between bed and wakefulness, not sleep.

Sleep Environment

Blackout curtains installed and sealed at edges— Even small amounts of light (streetlights, early dawn) can suppress melatonin and cause early waking.

No electronic devices in the bedroom— No TV, no tablet, no phone charging on the nightstand. Blue LEDs on devices disrupt sleep.

White noise or silence (consistent, not variable)— White noise at 50-60 dB masks environmental sounds. Avoid music or audiobooks that engage attention.

Mattress and bedding are clean and appropriate for temperature— Breathable materials (cotton, linen). Avoid synthetic fleece that traps heat.

If a nightlight is used, it's red or amber (not blue or white)— Red/amber wavelengths don't suppress melatonin. Even dim white/blue light does.

Weekend & Travel Consistency

Weekend wake time varies by no more than 30-60 minutes from weekdays— Sleeping in 2+ hours on weekends creates 'social jet lag' — the equivalent of flying across time zones.

When traveling across time zones, adjust light exposure to new schedule— Get morning light at destination local time. Avoid bright light at the 'wrong' time.

Maintain bedtime routine when away from home— Bring familiar items: white noise machine, blackout curtains (travel versions), same books or songs.

After illness or disruption, re-anchor wake time first— Don't try to fix bedtime. Fix wake time and morning light. The rest follows within 2-3 days.

The Big Three

If you can only fix three things, fix these: (1) consistent wake time, (2) morning outdoor light, and (3) screens off 2 hours before bed. These three changes address roughly 80% of circadian disruption in children.