Garmin’s dual heart rate monitoring: Innovation or intrusion?

A new Garmin feature that also causes some confusion, is the continued use of the optical heart rate (OHR) sensor built into the back of the watch even when users connect an external heart rate chest strap. It has left many questioning whether this is a bug or intended behavior. It turns out, this is by design

On the Fenix and Epix range, this behavior started after the the 16.00 Beta series. Previously, when you connect an external heart rate monitor, the watch’s OHR would switch off. That makes perfect sense. It’s a clear indicator that the Garmin watch is, indeed, utilising data from the external heart rate monitor (HRM). And it serves to preserve battery life on the watch itself.

The new behavior of keeping both switched on is being questioned on Garmin forums. A moderator stepped in to explain that the change is being introduced in order to support forthcoming features. And that this behavior is not in Beta.

“Yes this change is expected with 16.xx. We have some future features planned that are expanding on this behavior, and this (keeping OHR enabled) is required for that functionality once it is implemented. Stay tuned.” he states.

What exactly these new features are remains unclear. Perhaps it may even have something to do with automatic recovery heart rate calculations. This has been introduced in the latest Beta on some Garmin watches.

Why drain battery when using a chest strap?

The Garmin moderator offered further explanation. He stated that several reasons play into the decision to keep the wrist-worn heart rate sensor on:

• Consistency: Keeping both heart rate sensors active allows for more consistent heart rate and heart rate variability data throughout the workout. If one sensor drops data during the workout, the other will be able to continue recording uninterrupted.
• Garmin Pay: The OHR sensor’s continuous operation allows the Garmin Pay feature to work without hitches. It ensures the device remains in contact with the skin, averting the need for repeated PIN entries for consecutive transactions.

Workarounds for battery concerns

Garmin has also proposed solutions for users concerned about the potential increased battery drain due to the continuous operation of the OHR sensor:

• Manual deactivation: Users can manually turn off the OHR within the watch settings. However, it’s essential to remember to turn it back on afterward for everyday heart rate monitoring. This is done by going to Menu > Sensors and Access > Wrist HR > Change this to Off.
• Power Modes: Garmin’s Power Manager function enables setting up “Power Modes” with customized settings for individual activities. You can create a power mode that automatically disables the OHR when a specific activity is initiated. Do this by going to Menu > Power Manager > Power Mode > Create New > Select a Power mode, or select Create new > Ensure Wrist HR is disabled.

Is it the chest strap or the watch?

You might be left wondering how to tell if their heart rate data comes from the watch or chest strap. Garmin assures that if you record an activity while wearing a properly connected external heart rate monitor, your watch will primarily utilise that data. The only exception is when the chest strap drops the signal mid-activity; then, the watch’s heart rate sensor will take over to fill the gap.

Unfortunately, there’s no clear indicator on the watch itself to show which heart rate source is active. Users have requested a symbol or indicator to easily distinguish when the device is getting data from a chest strap as opposed to the wrist-based monitor. That would make sense – a simple tweak showing the source.

While Garmin’s decision to keep the OHR sensor active alongside an external HRM has its justifications, it also brings forth questions and challenges, particularly regarding battery life and data clarity. And even more importantly, it has left us in anticipation of a potential features Garmin might be planning to add to its watches.

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