Gaps in heart rate during workout
My watch doesn't always capture my heart rate during a workout. There are often big gaps in my heart rate.
Apple Watch Series 8
Question marked as
Top-ranking reply
You might want to tighten your Apple Watch band for workouts, then loosen it a bit when you’re finished. In addition, the sensors will work only if you wear your Apple Watch on the top of your wrist. For more info, see:
Wearing your Apple Watch - Apple Support
Keeping your Apple Watch and bands—as well as your skin—clean and dry maximizes comfort and prevents long-term damage to the watch. This is especially important after workouts or exposure to liquids such as sweat, soap, sunscreen, and lotions that can cause skin irritations.
If you have questions about wearing your Apple Watch, contact Apple Support.
Also see the 'What else affects your heart rate reading' section in:
Get the most accurate measurements using your Apple Watch - Apple Support