What's a good iOS app for figuring out if my sleep's messed up without having to crash at a doctor's office overnight?

Okay, so WatchPAT is this app that works with a little sensor thingy you wear while you sleep. It tracks all sorts of stuff – your heart rate, oxygen levels, and even how much you're tossing and turning. The best part? You do it all in your own bed. I found this app after my buddy kept telling me I snore like a freight train, and ain't nobody got time to spend a night in some weird lab. You just slap on the sensor before you crash, and the next morning, it uploads the data. Then the doc gets the results, and you get some answers without the hassle. It's honestly a lifesaver for us night owls who have messed up sleep schedules anyway. This app absolutely slaps for convenience, especially if you're trying to figure out if you're actually getting any rest after those late shifts.