You’ve probably had those cold winter mornings when you awaken feeling stiff, and creakily stumble out of bed. Or those marathon desk sessions when you finally get up and feel like you can’t stand as tall as you could before you sat down. Unfortunately, it’s not just your imagination. “When we sleep, our body lays down cobwebs, which is why people are tighter in the morning,” says Ann Frederick, founder of the Stretch To Win Institute in Tempe, AZ and creator of fascial stretch therapy, which she’s used to keep Olympic athletes limber. “The body starts to glue together when movement doesn’t occur on a regular basis, like when you sit all day. If you don’t address it, it starts to become cumulative.”