I’ve been tracking the amount of deep sleep I’m getting using my Apple Watch and I thought it was nowhere near enough — I asked a doctor and their answer surprised me

On the left, a close up of sleep tech writer Eve Davis wearing a sleep tracker while sleeping in bed. On the right, a close up of the Apple Watch Sleep Tracker showing the percentage for Awake, REM, Core and Deep Sleep.

Checking my Apple Watch sleep tracker has become an integral part of my morning routine — I love knowing what happened overnight to prepare me for the day. But one metric always seems low, leaving me worried a lack of Deep Sleep will cause my energy levels to crash by lunchtime.

Alongside hours in bed, the best sleep trackers observe the type of sleep you're experiencing during the night. My hours in light sleep, or Core Sleep on the Apple Watch, always dominate the night.