The Tool: Sleeptracker Pro wristwatch ($179, sleeptracker.com)
The Tout: Set the alarm for a window of time (say, between 6:30 and 7 a.m.). The watch tracks your sleep stages (between deep and non-deep) and rouses you within your time window during a less-deep period of sleep, leaving you more refreshed.
The Test-Drive: My eyes opened and the alarm sounded at exactly the same moment, after 7 hours of sleep but 13 minutes before the time I usually set my alarm for. “Your body is paralyzed in REM sleep,” says sleep expert Michael Breus, PhD, “and waking out of REM is very difficult. The device waits for you to move before waking you.” The Sleeptracker may not work for all people, though, especially those on antidepressants, since they get very little REM sleep.