You haven't been abroad, yet on Monday mornings your body feels heavy, as if you were jet-lagged. The phenomenon has a name: social jetlag. Up at 6 on weekdays, up at 10 on weekends — to your body clock, that four-hour gap is the same as flying to Spain and back every week. It's jet lag without the plane, and it sets in every Sunday night.
Sleeping in isn't "repayment" — it's manufacturing jet lag
Cut sleep on weekdays, pay it all back on the weekend. From the body clock's point of view, this whole idea of "catch-up sleep" contains a misunderstanding. Japan's Ministry of Health, Labour and Welfare's Sleep Guide for Health Promotion 2023 touches on the concept of "sleep debt" — lost sleep piling up like a loan — while pointing out that sleeping late into the weekend morning pushes the body clock backward and leads to feeling off at the start of the week. In other words, the weekend lie-in, meant as debt repayment, issues a different invoice: jet lag. Making up the shortfall isn't the problem in itself. The problem is making it up by moving your wake-up time.
The body clock resets with light each morning. Wake four hours later, and the light arrives four hours later too — the clock relearns that "this person's morning is 10 a.m." Then on Monday, at a 6 a.m. the clock still considers the middle of the night, only the alarm goes off.
If you shift anything, shift bedtime — not wake-up time
The principle behind the fix is simple: move your wake-up time as little as possible. The Sleep Guide, too, frames its advice around getting up at roughly the same time on weekends as on weekdays. If you're short on sleep, adjust by going to bed earlier, not by getting up later. Still, we understand the urge to sleep in at least on weekends. The rule of thumb often given as a realistic compromise is to keep the gap within two hours of your weekday time. Get up at 8 instead of 10, and if that's not enough, top up with a short daytime nap. That way you avoid winding the clock far back.
In our experience, this is less a matter of willpower than of scheduling. Put one thing you look forward to in the weekend morning — a walk, a market, the gym — and your wake-up time locks itself in. Rather than resisting the lie-in, give yourself a reason to use the morning. That's what lasts.
Redesign your weekend — just three changes
- Keep weekend wake-up within two hours of weekdays. Set the alarm for your weekday time; decide whether to go back to sleep after you're up
- Repay the shortfall with a nap. Thirty minutes or less, early in the afternoon. It's the only repayment method that doesn't compete with your night's sleep
- On Sunday night, err on the early side. For most people who dread Mondays, the dread comes paired with a late Sunday night. Sunday is the one night to give your bedtime a deadline
If sleepiness or feeling unwell persists for weeks, it may be something other than a rhythm problem. Don't hesitate to see a doctor.
