How does a sleep tracker on your finger compare to one in a bed? I tested Sleep Number and Oura for a month to find out. Plus, expert sleep-tracking tips. Aly Lopez Former Writer I Aly Lopez was a ...

Sleep is a moving target. When you were a newborn, you slept for most of the day, then less as an older child; as a teen, you slept later. A senior’s bedtime is earlier—part of a lifetime journey of ...