‘It tells me how much REM sleep I’ve had, how much deep sleep I’ve had how much I was laying in the bed wide awake,’ said Cameron. Many smart watches and fitness trackers claim to monitor sleeping patterns. “They are about 85 to 95% sensitive when it comes to measuring sleep duration,” said Dr. Tallvajhula. Ad“There are some sleep watches that gauge a drop in oxygen saturation which may be indicative of sleep apnea,” said Dr. Tallvajhula. “I don’t like any of the information that it gives me from my sleep count to my body fat percentage,” said Rahe.