Apple Watch Heart Rate Monitor Degradation

Hello juicepuppy,

This page can help out with providing a bit of information regarding items that can affect the heart rate reading, as well as how to get the most accurate measurements: Get the most accurate measurements using your Apple Watch - Apple Support

What else affects your heart rate reading

Many factors can affect the performance of the Apple Watch heart rate sensor. Skin perfusion (or how much blood flows through your skin) is one factor. Skin perfusion varies significantly from person to person and can also be impacted by the environment. If you’re exercising in the cold, for example, the skin perfusion in your wrist might be too low for the heart rate sensor to get a reading.

Permanent or temporary changes to your skin, such as some tattoos, can also impact heart rate sensor performance. The ink, pattern, and saturation of some tattoos can block light from the sensor, making it difficult to get reliable readings.

Motion is another factor that can affect the heart rate sensor. Rhythmic movements, such as running or cycling, give better results compared to irregular movements, like tennis or boxing.

If you’re not able to get a consistent reading because of any of these factors, you can connect your Apple Watch wirelessly to external heart rate monitors such as Bluetooth chest straps. Learn how to pair Bluetooth accessories.

Heart rate is one of many factors that Apple Watch uses to measure your activity and exercise. Depending on your workout, it selects the most appropriate inputs for that activity. For example, when you’re running indoors, it also uses the accelerometer. Learn more about how your Apple Watch uses GPS and the heart rate sensor when you use the Workout app. 

If you still have issues or questions then you may also use this link to reach out to the Apple Support Advisors that specialize in that area: Get Support

Cheers.