Short sleep accumulates, and the damage is not evenly distributed: attention recovers fast, glucose handling and mood take considerably longer.
Partial repayment is real
A weekend of extra sleep restores alertness measurably. It does not restore metabolic markers to baseline after several short nights.
Anchor the wake time
A consistent wake time with morning light does more for sleep quality than any evening routine, because it fixes the clock the rest of the day hangs from.
