Key points from article :
15 percent of U.S. adults own a wearable fitness/sleep-tracking device, such as Fitbit or Apple Watch.
Some people do take [quantified self] too far, and that can be stressful.
The claims of these devices really outweigh validation of what they have shown to be doing.
They are not able to differentiate between light and deep sleep.
The study was published in the Journal of Clinical Sleep Medicine.
