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Sleep Consistency Baseline: Timing and Duration Variability
14 consecutive mornings (2 min per morning) + 20 min to calculate variability metrics
Sleep consistency — regularity of sleep and wake timing — is a more powerful predictor of health outcomes than total sleep duration alone. Research consistently shows that irregular sleep timing disrupts the circadian rhythm, which governs metabolism, immune function, hormonal regulation, and cognitive performance. The most important metric is sleep timing variability: how much do your actual bedtime and wake time vary day to day? Establish a 14-day baseline (14 days rather than 7 captures the full weekly cycle including weekend variation, which is the most common source of inconsistency). Record each morning: actual time you fell asleep (as close as you can estimate), actual wake time, and total sleep duration in hours. Calculate the variability across the 14 days: the range from earliest to latest bedtime (in hours and minutes), the range from earliest to latest wake time, and the average total sleep duration. The NHS recommends 7–9 hours for adults. Social jet lag — the shift between weekday and weekend sleep timing — is particularly important; note if your weekend sleep timing differs from your weekday timing by more than 1 hour.
Proof required
Submit your 14-day sleep baseline: daily sleep onset time (estimated), daily wake time, and total sleep duration for 14 consecutive days. Calculate and report: bedtime range (earliest to latest), wake-time range (earliest to latest), average sleep duration, and whether weekend sleep timing differs from weekday timing by more than 1 hour.
What gets checked
- The baseline covers 14 consecutive days including at least one full weekend — 7-day baselines covering only weekdays systematically miss the weekend shift that is the most common sleep consistency problem; 14 days is the minimum for capturing the full weekly pattern
- Sleep onset time is the estimated time of falling asleep, not the time of getting into bed — for many people these differ by 20–60 minutes; using bed time rather than sleep onset time understates the variability
- The variability calculation identifies the range, not just the average — a person sleeping 7 hours consistently has very different health outcomes from a person averaging 7 hours but with a range from 4 to 10 hours; the range is the key metric
Common mistakes
- Using the time of getting into bed as the bedtime — bed-onset time (when you get into bed) and sleep-onset time (when you fall asleep) often differ by 30–60 minutes; using bed-onset time understates the variability and gives a falsely earlier bedtime
- Limiting the baseline to 7 days covering only weekdays — weekend sleep timing is the most common consistency disruptor; a baseline that misses the weekend produces an artificially consistent-looking baseline that does not predict the M2 challenge
- Not calculating the range — reporting only average sleep duration without the range misses the defining feature of sleep consistency; a person sleeping 5 hours one night and 9 hours the next averages 7 hours but is severely inconsistent
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- The baseline must cover 14 days and include at least one full weekend. If the submission covers only 7 days or only weekdays, ask for the extended 14-day baseline
- The submission should include the variability calculation (range), not just the average. If only average sleep duration is reported, ask for the bedtime and wake-time ranges
- The social jet lag note should be present — whether weekend sleep timing differs from weekday timing by more than 1 hour. If absent, ask the person to check whether their weekend bedtime and wake time are within 1 hour of their weekday times
Eight Weeks of Sleep Timing Consistency
8 weeks (2 min per morning for the daily log, weekly variability calculation at Weeks 2/4/6/8)
The 8-week programme targets a single primary intervention: narrowing sleep timing variability. The goal is a bedtime range of less than 45 minutes across all 7 days of the week, including weekends, and a wake-time range of less than 30 minutes. These targets are more important than total sleep duration because the circadian clock entrains (synchronises) to consistent timing; once entrained, sleep quality and duration typically improve naturally without additional effort. Choose a target bedtime and wake time based on the M1 average, adjusted to ensure 7–9 hours within the chosen window. The single most important rule: the wake time must be fixed even on weekends. Weekend sleep-in by more than 30 minutes effectively creates a weekly mini-jet-lag that disrupts the entire following weekday. The bedtime may drift by up to 45 minutes without consequence; the wake time must not. Log daily: actual bedtime, actual wake time, and whether the targets were met. Calculate weekly averages and variability metrics (range) at Weeks 2, 4, 6, and 8.
Proof required
Submit (1) daily sleep log for all 8 weeks showing actual bedtime, actual wake time, and whether each target was met; (2) weekly variability metrics (bedtime range and wake-time range) at Weeks 2, 4, 6, and 8; (3) a brief note at Weeks 4 and 8 on what specifically changed about the weekend sleep pattern.
What gets checked
- The daily log covers all 8 weeks including weekends — weekday-only logs do not test the primary consistency challenge; if weekend days are missing, ask for them
- Weekly variability metrics show bedtime range and wake-time range separately — an average bedtime does not reveal whether individual nights fell within the 45-minute target window; the range is the key measure
- The Week 4 and Week 8 notes specifically address weekend sleep timing — the most common consistency failure is maintaining the plan on weekdays while reverting to a late wake time on weekends; the notes must address this explicitly
Common mistakes
- Maintaining a consistent weekday sleep pattern while allowing a 2+ hour weekend sleep-in — this is the most common failure pattern; it resets the circadian clock every week and eliminates most of the programme's benefits
- Focusing only on moving bedtime earlier without fixing the wake time — wake time is the primary circadian anchor; adjusting bedtime without fixing wake time is the less effective intervention
- Setting a target bedtime that requires sleeping fewer than 7 hours (e.g. targeting midnight to 6 am to 'force the pattern') — circadian consistency combined with insufficient sleep duration is worse than inconsistent sleep at adequate duration; the target window must allow 7–9 hours
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- The daily log must include weekend days. If only weekday data is present, ask whether the person simply did not submit weekend logs or whether the consistency programme was only applied on weekdays
- The weekly variability metrics should show separate bedtime range and wake-time range, not just averages. If only averages are reported, ask for the range values
- The Weeks 4 and 8 notes should specifically address weekend sleep timing. If the notes are vague or do not mention weekends, ask the person directly whether their weekend wake time stayed within 30 minutes of their weekday wake time
Final Sleep Consistency Comparison
14 consecutive mornings (2 min per morning) + 20 min to compile comparison table at the end of Week 8
At Week 8, complete a final 14-day sleep log (to match the M1 baseline length and include a second full weekend). Record actual bedtime, actual wake time, and total sleep duration each morning for 14 consecutive days. Calculate variability metrics using the same method as M1: bedtime range (earliest to latest), wake-time range (earliest to latest), and average sleep duration. Compare M3 to M1 in a side-by-side table. Provide an attestation from one named person who was present during the 8-week programme — a household member or partner who can describe what specifically changed about the person's sleep timing, especially at weekends.
Proof required
Submit (1) M3 14-day sleep log (actual bedtime, actual wake time, total duration for each day); (2) a side-by-side comparison table of M1 and M3 variability metrics (bedtime range, wake-time range, average duration, social jet lag note); (3) an attestation from a named person who observed the sleep pattern change across the 8 weeks.
What gets checked
- M3 covers 14 consecutive days including at least one full weekend — matching the M1 baseline length makes the M3 variability metrics directly comparable
- The comparison table shows both variability metrics (bedtime range and wake-time range), not just average duration — average duration is a secondary metric; variability reduction is the primary outcome of this programme
- The social jet lag note is updated for M3 — whether weekend sleep timing now falls within 1 hour of weekday timing; this is the key observable change that the attestation person should be able to confirm
Common mistakes
- Using only 7 days for M3 rather than 14 — the M1 baseline was 14 days to capture the full weekly cycle; a 7-day M3 uses a shorter window that may miss weekend behaviour and makes the comparison asymmetric
- Calculating M3 variability only for the final 7 days of the programme rather than the final 14 days — variability measured over 14 days includes two weekends and is more representative than a 7-day window with one weekend
- Providing an attestation from someone who only observed the final two weeks and not the beginning — the attesting person must have been present throughout to describe what changed
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- M3 must cover 14 days including at least one full weekend. If only 7 days are submitted, ask for the remaining 7 days
- The comparison table must show variability metrics (bedtime range and wake-time range), not just average duration. If only average duration is compared, ask for the range metrics
- The attestation should specifically note whether the person's weekend sleep timing changed compared to before the programme — this is the most visible and meaningful indicator of sleep consistency improvement