How can I track sleep time on an Apple Watch?

Cardiogram previously supported automatic sleep tagging by importing sleep sessions from Apple Health. However, changes in how Apple now structures sleep data have affected this feature.

💤 Why automatic sleep tagging was removed

Apple introduced sleep stages (light, core, deep, REM), which are now saved as separate "sleep sessions" in Apple Health. Because Cardiogram pulls raw sleep data from Apple Health, these sleep stages appear to us as multiple overlapping sleep entries.

Our current system cannot yet distinguish between full sleep sessions and individual stages. This led to duplicate or confusing sleep tags on user timelines. To avoid this, we’ve temporarily removed automatic sleep tagging for Apple Watch users.

We are actively working with Apple to improve this, and we hope to restore this feature in the future once the raw data becomes easier to interpret.

✅ What you can do instead

Option 1: Manually tag your sleep in Cardiogram

1. Open the Timeline in the Cardiogram app
2. Tap the three dots (•••) on the day you want to tag
3. Select Add Tag
4. Choose the sleep duration and label it appropriately

This ensures your Timeline still reflects your rest patterns.

Option 2: Use a third-party sleep tracking app

Apps like SleepWatch and Pillow can track your sleep and write the data to Apple Health. Cardiogram can then read that sleep duration and display it in your Timeline.

💬 Need help?

If you’re unsure how to tag your sleep or connect third-party apps, we’re here to help. Email us at [email protected]