**There is no official nightly target for deep sleep on its own; aim for 7 or more hours of total sleep a night and your body decides how much deep sleep it takes.**
Deep sleep, also called slow wave sleep, is the stage where your breathing and heart rate slow and your body does much of its physical recovery. Most of it happens in the first few hours after you fall asleep, so cutting your night short trims deep sleep first. The share of the night spent in deep sleep drops naturally with age, and it also falls after alcohol, late caffeine, or a disrupted schedule. Wearable sleep scores estimate stages rather than measure them, so treat them as a rough trend and not a diagnosis. Steady bed and wake times, a dark cool room, and daytime light exposure do more for deep sleep than any single fix.
How to get more deep sleep
Common questions
how much deep sleep do you need
Deep sleep is not something you set a separate goal for. Health agencies give targets for total sleep: 7 or more hours a night for adults, and more for teens and children. Within that time, most adults get their deep sleep in the first half of the night, and the amount declines with age, which is normal. The dependable way to protect it is to allow enough time in bed, keep a consistent schedule, limit alcohol and late caffeine, and get evaluated for loud snoring or pauses in breathing. See a clinician if you sleep enough hours but still wake unrefreshed most days.