Answer;
The above statement is true
One type of personal health monitor measures the amount of time you spend in REM sleep.
Explanation;
-Fitness tracker or monitors have the ability to monitor or track the shut-eye during sleep.
-These trackers all continuously monitor the movements of the eye during sleep and also assess sleep-wake cycles to ascertain whether an individual is in deep or light sleep.
-Some of the trackers incorporates heart rate data to get a better sense of how deep one is into their sleep.