by POPSUGAR Fitness 6

You've worked hard all week, so when Friday comes around, you go out with your gals and celebrate. That's awesome. You stayed out late, so you sleep in on Saturday morning. The same thing happens the next day.

When Monday hits, it hits you hard. Why is it so impossible to wake up? Mondays suck, right?

Sorry for the wake-up call, but sleeping in throws off your body's circadian rhythms. That's why you feel sleepy and have a hard time getting up after a weekend of sleeping in.

Fit's Tip: Here's an idea that just might make Mondays a little easier to swallow. Don't sleep in on the weekends. Get up the same time you do during the week - set your alarm if you need to.