Image source: Garmin

Garmin Forerunner users rejoice: Lactate Threshold detection fixed in Beta update

Users of Garmin Forerunner watches have been frustrated by an on-going problem with lactate threshold. The detection of this crucial measure has not been functional for a while. The good news is that Beta software update 15.09 finally provides a resolution.

The issue affected the majority of Forerunner timepieces, including the 265 and 965 that were just launched, along with the 955 and a few others. Lactate threshold detection was working fine up until mid-January, but users complained that Garmin Connect was not updating the numbers.

The problem was resolved briefly and both detection and uploading functioned well from the middle to the close of January. In February and March both stopped. Garmin had confirmed at the time that they are aware of the issue and are actively investigating the root cause.

The fix has arrived – but it’s still in Beta

If you are enrolled in the Beta programme, you can now download a fix. It is part of update that goes under the number 15.09. So downloading that or a subsequent version of the software should resolve the problem. Users on Garmin forums have confirmed that this is, indeed, the case.

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Confirmation can also be seen in the change-log of version 15.09.

“Fixes an issue that could prevent lactate threshold heart rate auto-detection from working correctly.”

Why this is a important

The lactate threshold metric will be familiar to serious runners. It is an essential indicator of performance because one of the best indicators of success in endurance sports is the capacity to maintain exercise at or near the lactate threshold. By increasing the body’s ability to clear lactate, the muscle’s capacity to act as a buffer, and mitochondrial function, training at or just above the lactate threshold can enhance endurance capacity.

Garmin Lactate Threshold

Garmin watches use a combination of heart rate data and GPS tracking to estimate a person’s lactate threshold. This is based on the relationship between heart rate and exercise intensity. If you wear a heart rate chest strap during your run and exert yourself sufficiently for an extended period of time, this is updated automatically.

Garmin Lactate Threshold

The other option is to do a Garmin lactate threshold test. Usually, a user must warm up for 10 to 15 minutes at a leisurely pace before beginning the 20-minute time trial effort. The goal of the time trial is to maintain the highest sustainable pace. After the test is complete, the Garmin watch determines the user’s lactate threshold based on the heart rate during the exercise.

Once a user’s lactate threshold has been estimated or measured, Garmin watches use this information to set training zones. These can be based on heart rate, power, or pace. Depending on a user’s goals, the zones assist athletes in training at the proper intensity to increase their endurance, speed, or power. For instance, the Garmin watch can recommend training sessions that include intervals performed just above or below the lactate threshold to improve an athlete’s endurance capacity if their lactate threshold is known.

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Marko Maslakovic

Marko founded Gadgets & Wearables in 2014, having worked for more than 15 years in the City of London’s financial district. Since then, he has led the company’s charge to become a leading information source on health and fitness gadgets and wearables.

One thought on “Garmin Forerunner users rejoice: Lactate Threshold detection fixed in Beta update

  • if you’ve read the garmin forums you should know that this has been an issue off and on for some users at least, for months – probably since first release 9 months ago.

    this is just one of many bugs in the 955 software, not even one of the most significant ones. they all seem to persist past updates supposedly fixing them.

    its great that someone is finally publicising some of this but you could go a lot further.

    readers should note that the same issues likely affect 255, 265, 955 and 965 watches since they share the same base software


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