Yesterday was a holiday, so I overslept till noon. To be honest, I was indulged in a nice computer game for a week, and it was getting rid of my sleeping time, shamefully.
Oversleeping is actually harmful to your health. Indeed, I woke up today with a little depressed mood.
Studies suggest that changing sleeping schedule on the weekend is an unhealthy habit. Persons with shift-time sleeping were likely to have greater risks of metabolic syndrome.
The New York Times: Sleeping In Feels So Good, but May Be Unhealthy
This study was conducted at the University of Pittsburgh. Healthy working volunteers were recruited to assess their chronotype and the state of social jetlag. As a result, participants with taking more sleep by more than one hour in holidays than usual had higher triglycerides, and insulin level.
Journal of Clinical Endocrinology and Metabolism: Social Jetlag, Chronotype, and Cardiometabolic Risk
This study is cross-sectional. Thus, it is unclear that social jetlag is a cause of metabolic syndrome. It is possible that unhealthy people cannot take enough sleep in working days. But I think this result does make sense.
The brain remembers the lack of sleep for a couple of weeks, according to a researcher. If it is true, it is rational to compensate the sleeping time in a holiday. On the contrary, you should not take a long-time sleep after the night you could not sleep well, in a modern theory of sleep science. Waking up at the same time every day is recommended, regardless of sleep quality and quantity to maintain your physical health. I feel it is difficult to carry out, though.