Definition
- Social jetlag
- Social jetlag is the mismatch between your body clock and your social schedule, measured as the difference between your sleep timing on work days and free days. A two-hour difference produces effects comparable to travelling across two time zones every week.
Why weekends make Monday worse
Sleeping in on Saturday and Sunday shifts your circadian rhythm later. By Sunday night your body clock expects to sleep later than your Monday alarm allows, so you both fall asleep late and wake unrefreshed — then repeat the cycle.
The intervention that helps most is keeping wake time roughly constant, within about an hour, including at weekends. It is unpopular advice and it is also the most effective.