Data from a sleep tracker is just not comparable to what is shown in the overnight assessment used by sleep specialists to diagnose sleep disorders, Meir Kryger, MD, tells Bottom Line Inc.

For some people, to be sure, tracking how much sleep they get (even if it’s not a perfect measure) is useful. It’s like using a device—maybe even the same one—to count how many steps you take every day. If that step counter tells you even roughly that you aren’t taking enough steps, you can fix that—just walk more. Similarly, if you aren’t sleeping enough, you can make an effort to get more rest.