Measure how consistent your sleep schedule is.
Consistency has two components: how much your weekday times wander, and how far the weekend pulls them later. The second is social jetlag, and it is weighted heavily because a two-hour weekend shift is the circadian equivalent of flying across time zones every week. Wake time regularity matters more than bedtime regularity, since it anchors light exposure and the clock that follows it.
Consistency score
Score = 100 - (average weekday variation x 0.5 + weekend shift x 0.35), floored at 0; average variation = (bedtime variation + wake variation) / 2
These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
The mismatch between your body clock on work days and free days, measured as the shift in mid-sleep time. Two hours or more is associated with poorer metabolic and mood outcomes.
Wake time. It sets your light exposure and therefore anchors the circadian clock; bedtime tends to follow once wake time is stable.
Partially — some recovery occurs — but a large weekend shift also delays your clock, which makes Monday harder. Limiting the lie-in to an hour is the usual compromise.