The Nocturnal Battery Drain
The Apple Watch includes a built-in Sleep Tracking feature that monitors your heart rate, movement, and blood oxygen levels while you are in bed. While useful for analyzing your sleep stages, leaving a smartwatch strapped to your wrist all night is uncomfortable for many users. More importantly, running all of those biometric sensors continuously for 8 hours drains a massive amount of battery life, virtually guaranteeing your watch will die halfway through the next workday. If you prefer to charge your watch at night, you must completely disable the sleep tracking engine.
How to Turn Off Sleep Tracking
You can permanently sever the watch’s ability to monitor your nocturnal biometrics via the Sleep settings.
- Open the Settings app directly on your Apple Watch (the grey gear icon).
- Scroll down the main list and tap on Sleep.
- Scroll down to the “Sleep Tracking” section.
- Locate the toggle switch labeled Sleep Tracking.
- Toggle this switch to the Off position (the green background will disappear).
Restoring Battery Life
The change is instantaneous. The Apple Watch will completely terminate the background daemon responsible for parsing accelerometer and heart rate data during your scheduled bedtime hours. You can still set morning alarms using the standard Alarms app, and you can still utilize the “Sleep Focus” mode to silence notifications on your phone, but the watch itself will absolutely never again attempt to log your biometric sleep data, saving critical battery life for daytime use.