Last week in The Times, I reviewed a weird, wonderful, sleep-tracking alarm clock called the Zeo. It's a $400 bedside alarm clock that comes with a wireless headband that monitors your brain waves. In the morning, the clock's screen shows you a graph of your night's sleep cycles (light sleep, deep sleep, dream sleep, waking).
In that column, I promised to review another sleep-monitoring gadget that doesn't require strapping anything onto your forehead: the Sleeptracker watch ($180, sleeptracker.com). It's a fairly homely black plastic watch and band with four buttons and a big, clear L.C.D. digital screen.
This watch makes no attempt to monitor your brainwaves. (Unless you're a spectacularly loud thinker, that'd be quite a feat, all the way down on your wrist.)
It also makes no attempt to identify which sleep phase you're in, upload the data to the Web, or give you personalized advice, as the much more expensive Zeo does.
Instead, the Sleeptracker watch contains a tiny motion sensor--an accelerometer, like the one in the iPhone. It attempts to identify, by your restless nighttime movements, the moments during the night when you nearly wake up (or wake up momentarily but don't remember). Those are either the moments *between* sleep cycles or wakeups from environmental factors like pets or city noises.
What's the point? Two, actually. First, you can connect the watch to a USB cable and upload a record of the night's near-wakeups to a companion Windows program. It shows you a timeline of each night's sleep, with tick marks that represent those near-wakeups, and a place to record factors like caffeine or naps so that you can spot correlations.
I doubt many people will stick with this past the novelty phase. The watch stores only one night's worth of data. So if you truly want to track your sleep, you have to perform the entire ritual every single day: take off the watch, set it to Data mode, connect it to your Windows computer, fire up the software, click the Upload button. It's a lot of work, and the results aren't especially enlightening.
Furthermore, the watch tracks your sleep only if you tell it what time to start and stop tracking.
Unfortunately, despite its name, the Sleeptracker doesn't actually know when you're asleep. You have to tell it ahead of time when you *expect* to fall asleep. (If you're still awake at that hour, you have to guess-program it again. And so on.)
As for the stop time, that's the alarm time (read on). In other words, the watch doesn't track your sleep on days when you don't set an alarm.
The watch's primary feature, though, is that it tries to wake you (by vibrating, beeping or both) at the best possible time, within an "alarm window" that you specify.
For example, if you have to be up by 7 a.m., you set the watch's alarm to 7:00, but you might set the alarm *window* to 30 minutes. If, in that last half hour before 7, the watch senses that you're having a near-wake moment, it goes off early.
The idea is to wake you when you're nearly awake anyway. That way, you avoid the groggy, out-of-it-for-hours feeling of "sleep inertia," which happens when you're awakened from a deep sleep.
It's a little hard to believe that somebody who got *less* sleep could feel more refreshed than someone who got *more* sleep. But that, in fact, is what the Sleeptracker promises. (The Zeo offers the same feature. So does the Axbo alarm clock, which I haven't tried.)
Does it work?
Well, during my two weeks wearing the watch, I never woke up groggy. The thing is, it's hard to say whether I would have felt fine on those days anyway.
(One absolutely great feature, though, is that the vibrating can wake you without waking your sleeping partner. Or vice-versa. Now *that's* a key to better sleep.)
Most of the customer reviewers on Amazon write that the alarm-window concept really works; many write unequivocally that they rarely wake up groggy anymore. (The watch has received a lot of poor reviews, too, but most cite a too-quiet beeper alarm. I didn't experience that problem with the current model, the Elite.)
Some, on the other hand, reported no change in their grogginess. (I especially liked this one: "This gadget does what it promises: wakes you up when you are almost awake. Having said that, I am still grumpy no matter what. And being woken up 15 min before my alarm rings just makes me even grumpier.")
Note, too, that a number of reviewers have noted how easy it is to shut off the alarm clock when you're wearing it--and go back to sleep. You don't even have to reach over to the nightstand.
So this watch's wake-me-at-the-perfect-time system won't work for everyone. The thing has some baffling design quirks, the software is crude, and it won't win any fashion awards.
But I'm a big believer in, and worrier about, the sleep-deprivation problem. You only have one life, and going through it exhausted diminishes just about everything worth enjoying: relationships, productivity, creativity, feeling good.
So if there's even a chance that it could improve your quality of life, you should try the Sleeptracker (or the Zeo). There's a 30-day guarantee, which makes that experiment even more palatable.