The feature allows you to set a recurring bedtime reminder and morning alarm based on the amount of sleep you want to get. (health.com)
For more precise tracking, though, manual options continue to be available.Today's Sleep + + update also includes other features like bedtime reminders, notifications with a summary of the previous (macrumors.com)
For me, the 15 - minute bedtime reminder has served as a good prompt to put my phone away and turn the lights out. (health.com)