Garmin users beware: Is Dynamic Source Switching wrecking your run data?

Garmin has recently rolled out a new feature called “heart rate dynamic source switching.” This feature, initially introduced in beta versions, is now available in public software updates for the recent crop of Garmin watches. While promising improved accuracy during running activities, some users are reporting significant issues that raise questions about its reliability. Here is what you need to know and how to switch off the feature.

Dynamic Heart Rate Source Switching – what is it?

The core concept of dynamic source switching revolves around the idea of selecting the optimal heart rate data source in real time. Garmin describes this feature as a way to seamlessly switch between the watch’s built-in optical heart rate sensor and an external heart rate monitor (HRM) if the software determines it’s necessary. This automatic switching aims to ensure the most accurate heart rate data possible during your runs. At least, that’s the idea.

However, Garmin hasn’t explicitly stated the exact conditions that trigger the switch. Speculation among users suggests it could be a workaround for the unreliability of some Garmin HRM-Pro straps after prolonged use, but the feature is designed to function with any external heart rate monitor.

Feature is far from ideal

The concept of dynamic source switching sounds promising. For example, a heart rate strap may struggle to capture accurate readings at the beginning of runs. This is often referred to as start-up noise. So it might be useful to temporarily switch to wrist-based readings in this instance.

However, the reality for some users has been far from ideal.

One of the issues reported involves extreme heart rate spikes. These drastically high heart rate readings, potentially due to conflicts between the watch’s sensor and the external monitor, have raised concerns about data accuracy. This is particularly problematic for those using Garmin’s Max HR auto-detection feature, as inaccurate data can lead to incorrect training zones and potentially harmful training plans.

Another problem reported by users is the occurrence of data gaps during activities. These gaps in heart rate data can be frustrating for those who rely on accurate and continuous data to track their progress and training. It is particularly problematic when engaging in activities such as HIIT.

How to switch off the feature

Given these reported issues, the question arises: should you disable dynamic source switching? If you’re experiencing problems, disabling the feature might be a sensible course of action. To do so, hold the centre left Menu button > Select the gear icon for more options > select Health & Wellness > Wrist Heart rate > Source Switching. And select “Disable”.

Essential reading: Top fitness trackers and health gadgets

Disabling this feature will force the watch to rely solely on one heart rate source – either the wrist sensor or the external monitor. If you have a reliable external HRM, this is often the preferred choice for accurate data, as chest straps are generally considered more reliable than wrist-based optical sensors.

Garmin’s dynamic source switching feature may hold the potential to be a valuable tool for runners and other athletes. However, the reported issues highlight the need for Garmin to refine the feature’s algorithms and improve the user experience. Until then, users should be aware of potential problems and be prepared to disable the feature if necessary.

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