HR not monitored at the beginning of a workout

Hi Marion - I had exactly the same characteristics as you have described. My AW 6 on my left wrist was hopelessly inaccurate and very unreliable. It was ok on a walk most of the time but not on a run. Sometimes it would take several minutes to start recording and sometimes it would stop recording during the run. My left wrist is thinner than my right wrist and the veins on my right wrist are more prominent so I swapped the watch to my right wrist and started wearing wrist sweat bands (that I normally wear in the summer) to help hold my watch in place without having to tighten the strap too much. That worked really well but still had the occasional glitch. I then bought a braided solo loop band (non Apple) off Amazon and since changing to that my heart rate monitoring has been perfect on every run. The braided solo loop band is much more comfortable than the Nike sport loop and it holds the watch in place far more effectively without needing to be tight. It also looks a lot nicer too. I also end up without the indented marks on my wrist that the Nike strap used to leave. Feel free to discuss further - we can sort this.

Hi Marion___,

Thanks for coming to Apple Support Communities for help with your Apple Watch. As we understand, your heart rate isn't being monitored the first 20 minutes of a workout.

Have a look at this page: Get the most accurate measurements using your Apple Watch. Be sure to work through all the steps, but also see the last section:

"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 the issue continues, let us know.

Have a fantastic day!

Try changing the fit of the strap on your wrist or the position on your wrist (further up your arm) or change wrists. The AW 6 is quite temperamental and and sensitive to fit and position. Took me a while to get mine working properly.

Hi Marion,

Thats great to hear - well done. When I went that route I hoped it would work but was surprised at how well it worked. I’d almost resigned myself to not bothering to record my heart rate but now it’s sorted I’ve changed my view of the AW completely. Glad it helped you too.