You probably wake up 8-11 times a night - plus 21 other discoveries from sleep-tracking apps

Why is it that you can go to be on time and wake up feeling exhausted?

Perhaps you are waking up more than you think you are.

For most of us, getting enough sleep is a problem.

But thanks to fitness trackers like Fitbit, Jawbone UP, and sleeping-aid apps like Sleepio, we now have all sorts of data on how we sleep and how to improve our rest.