Latest research highlighted over at the Telegraph says that sleeping in on the weekends does nothing to revitalize any sleep that you might have missed out on during the busy weekday. In fact, attempting this might actually make you feel more lethargic once Monday kicks in. The reason why is because the circadian cycle lasts 24-hours, and
sleeping in will only confuses the body's natural sleep cycle:
The body can accommodate a delay to the circadian clock of up to an hour, meaning that a short lie-in at weekends is unlikely to have any significant effect on tiredness on a Monday morning.
However, delays of up to two hours or more can throw the body out of sync, making it more difficult to get to sleep on a Sunday night and even harder to get out of bed the following morning.
Any “sleep debt” built up by going to bed too late during the week can be balanced out on Saturday or Sunday simply by getting eight hours of sleep, because the brain rests more efficiently when someone is tired, said Dr Carter.
So no matter how hard you try, you can't fool your circadian clock. Instead, sleep experts like Dr Gregory Carter at the University of Texas Southwestern recommends you counteract with your tiredness by going to bed earlier on the weekends.