Garmin Forerunner Pace Alerts Don’t Make Sense

The TL;DR is that Garmin’s pace alerts seem to trigger on average pace but the alert on the screen shows current pace. It can be confusing especially early on in a run where the average is much more volatile.

Garmin Coach

I own a Garmin Forerunner 245 GPS watch and use it track my runs, bike rides, and any indoor activities. I also have an Apple Watch Series 4 with Cellular but don’t use it for tracking any longer because of weird GPS behaviors. The Forerunner 245 has definitely been a superior GPS unit and their biometrics (especially with their heart rate strap and sensor package) blow the Apple Watch out of the water.

In 2019 I ran way more than I biked and discovered I was also getting faster and had higher endurance. I like to close the red activity ring on my Apple Watch every day and it’s really my only fitness goal beyond using exercise to help combat my ADHD. I was discovering after several months of running every day (3-5mi on average) that my body was getting fatigued sometimes, lasting a week or more before recovery. I really noticed this when I started running more on trails in a nearby park influenced by glaciers.

I got the Forerunner watch in late 2019 and discovered the Garmin Coach plans really soon after installing their app. I don’t run in races nor do I really have any speed or distance goal. I ran a half marathon distance without specifically training and I recovered from it just fine. What I did want to start learning to do was how to vary my workouts with intention and include specific rest days. So, the Garmin Coach plan seemed like a great thing to follow.

I never ran with a specific pace in mind, only ever looked at the results after a run. I wanted to run smarter, and maybe a bit faster on longer distance runs. I may some day decide to enter a race, but again, not a factor for me.

Different Types of Runs

Garmin coach has several different run types that I’ve encountered so far in the plan with the “coach” I’m using:

  • Time trial – short distance runs near your threshold speed to gauge progress to your goal.
  • Easy run – slower runs in a 2-6 mile range.
  • Long run – 6-11mi runs (they keep getting longer towards my half marathon distance goal).
  • Speed intervals – oscillate between hard/threshold runs for 30-90 seconds, then recovery slow run for the same time.
  • Tired legs – an open-ended run once a week that lets you decide your pace.

Pace Alerts

I was really happy to see that the Forerunner gave me audible and visual alerts when my pace was outside of the target zone in the plan. I was not “good” at keeping a consistent pace so this was a great tool to learn control over pace.

During the run on the watch one of the data screens shows the pace range and where you’re at.

If you go outside the threshold, you get a pace alert.

The frustrating thing is the pace alerts never really make sense because there are times the alert shows a pace that’s well within the range you’re supposed to be at. In this example my pace should be 9:17-9:47 min/mile. After I took the picture of being at 9:20 I ran much faster (I was actually at closer to 7:30 min/mile) for nearly a quarter mile before the alert came up. I had started to slow down going up a hill before the alert triggered.

What I’ve Figured Out

Garmin’s documentation is super sparse and most people online blame “GPS inaccuracies” any time someone questions behaviors like this. I think I’ve gotten it figured out with what’s going on.

  • Pace alerts are based on the average pace for the segment you’re in. When you set up a workout plan (or get them from a Garmin Coach plan) the pace is set for a particular segment as shown in the screenshot above. I also don’t think it’s just a regular average, it feels like it’s weighted or a rolling timeframe.
  • Earlier on in a segment, pace alerts are more sensitive because your average speed is volatile with less distance. The alerts come up more often even if you’re trying to stay really close to the edge of the acceptable range.
  • Stopping or walking to take a breather can lower your average speed, letting you unintentionally run faster for a short period of time after. This seems like a “no duh” thing but if you stop for any reason – waiting for a traffic light or whatever – it’s easy to exceed your pace range and not get alerted about it for some time. Then you’re surprised that you’re running faster than you should be.
  • Instant pace is not super accurate and it’s rounded to five second marks. Pace alerts are to the second so they don’t match the instance pace you see on the first data screen.

Even with knowing all this, I still feel like there’s some software programming glitches making the alerts not logical to us users. It’s really hard to capture what’s happening because, well, you’re running and you can’t reproduce it easily for a technical support case with them.

So use the pace alerts to help guide you and if they end up annoying you, turn them off.

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