An article on “social jet lag“, an interesting way of looking at the jet lag caused by different sleep schedules on weekends vs weekdays:
Roenneberg, who coined the term, says social jet lag is brought on by the shift in sleep schedule that many people experience on their days off, compared to work days. He estimates that it affects about two-thirds of the population.
It goes like this: You don’t have to get up for work so you don’t bother setting the alarm. That means you get up an hour or two later than you might during the work week. You may also push your bedtime back so you can go out with friends.
As a result, many people get more sleep on their days off than they do during the week, and they sleep on a slightly different schedule — a schedule that is closer to their body’s natural rhythms.
Roenneberg explains that switching sleep schedules this way feels like changing time zones.
"The behavior looks like if most people on a Friday evening fly from Paris to New York or Los Angeles to Tokyo and on Monday they fly back. Since this looks like almost a travel jet lag situation, we called it social jet lag," he says.
A key difference between travel jet lag and social jet lag, however, is light. When you arrive in a different place, the sun is coming up and setting at a different time, and your body can reset its own clock to match.