How Garmin Performance Condition Works: What You Need to Know

Your Garmin watch uses several basic data points to calculate a bunch of different fitness stats. Today, let’s talk about Garmin performance condition.

What is it? How does it work? Why should you care?

In short, the performance condition metric on your Garmin is an estimate of how well you are running on a particular day. A positive performance condition means you’re well rested and performing well. A negative performance condition means – for one reason or another – you’re not running as well as usual.

But there’s more to it than that. So let’s get to it.

Note: Performance condition is available on most, but not all, Garmin watches. The entry level watches, like the Garmin Forerunner 55, don’t have this feature. For more on choosing the right watch, check out this guide to buying a Garmin Forerunner.

How Is Garmin Performance Condition Calculated

In order to understand how performance condition is calculated by Garmin, you first have to understand the Garmin VO2 max estimate. You can read an entire article on that here, but here’s the quick version.

Garmin uses your max heart rate, along with pace and heart rate data from your run, to calculate your VO2 max. This is an estimate of your overall fitness.

With this estimate, Garmin can predict what pace you should be able to run at a given intensity. For example, based on historical data and its algorithm, Garmin assumes that you can run at a sustained pace of 9:00 min/mile with a heart rate of 140.

Performance condition is a snapshot of a moment in time – compared against this estimated VO2 max. If you’re running faster than expected, your performance condition will be high. In this example, let’s say you’re out for a run and you’re cruising along at 8:30 min/mile but your heart rate is still 140. The measured intensity is the same, but the pace is quicker than expected.

If you’re having a bad day, the opposite is true. Instead of feeling good, you’re dragging from a hard workout. You’re plodding along at 9:45 min/mile, but your heart rate is still registering 140. You’re running much slower than Garmin expects – yielding a low performance condition.

Is Garmin Performance Condition Accurate?

If you read my post about Garmin’s VO2 max algorithm, you know that you need to take the VO2 max estimate with a grain of salt. So if that number isn’t always accurate, should you expect performance condition to be accurate?

In my experience, it usually is. But not always.

Part of the problem with the VO2 max algorithm is that it isn’t valid – but it’s often reliable. In scientific terms, that means that it might estimate the wrong number. But it consistently estimates the same wrong number over time in the same situation.

With that in mind, Garmin may or may not have an accurate assessment of your VO2 max. But if it applies the same imperfect algorithm to all of your runs, it is still setting a baseline against which it can make a useful comparison. And once your Garmin has figured out what pace it expects you to be able to run at a given intensity, it can be fairly good about noticing when things are or aren’t going well.

It also tends to match up with my own perception of effort. About 5 to 10 minutes into a run, my watch buzzes and gives an initial reading of performance condition. On days that I’m ready to rip and run, it’s often positive. These are the days that I cruise along faster than usual, without putting in a lot of effort. But on the days after a tough workout, when I’m shuffling along for the first mile or two, I’m not surprised to see a negative number pop up.

What Impacts Performance Condition?

There are a number of factors that may influence your performance condition. Some of these you should take into account – and some you should probably ignore.

Fatigue

First up is fatigue. When you’re legitimately tired from a hard effort, you’re going to struggle to maintain your normal pace.

From day to day, this is often going to show up in your recovery runs following hard workouts. If you put in a really tough workout on Tuesday – or especially if you just ran a race – you should expect to see a negative performance condition.

Throughout the course of a long run, you might also expect this number to fall. Some long runs I feel great, and I look back to see that my performance condition was positive throughout. But other times – when the weather is hot or when I was first pushing the limits on distance – I would find that it would drop off a little in the second half of the run.

You probably shouldn’t be too concerned about fatigue from one day to the next. But if you’re consistently dropping off over the course of a long run, you might want to take stock of your training.

Weather

Weather impacts performance. It’s heating up in New Jersey right now, and I’m reminded every day that summer sucks.

Here, performance condition can be useful to help you do a spot check of how the weather is impacting you on a given day. If you’re going out for a long tempo workout and it’s a little hotter than usual, you may want to adjust your pace.

I’ve ignored the signs, tried to run my planned paces on a hot day, and paid the price. And so if it’s hot and sunny, and my performance condition comes up negative during my warm up, it’s a sign that I might want to back off a little bit.

That doesn’t mean I won’t do the workout. But I usually have a 10 to 15 second range in mind for a workout pace. On a good day I might be more aggressive towards the fast end. On a bad day, I’ll back off and stick with the more conservative end of the pace range.

Hills and Elevation

Over the course of a workout, hills and elevation may not matter too much. But if they are strategically placed in the wrong spots, they can really mess up your performance condition estimate.

Your watch takes 5 to 10 minutes to come up with an initial estimate. The idea here is that you’ve warmed up and gotten into a groove.

But what if a lot of those first 5 or 10 minutes was uphill? You’re going to be running slower and working harder than usual. And this can inadvertently lead your watch to think that you’re having a lousy day.

This is where you want to remember that the metric isn’t perfect. If you started out with a hill, and your performance condition is lower than you expected, you might want to wait until you get to a flatter portion of your run and check it again.

Inconsistent Running

Another thing that will mess with the algorithm is if you don’t keep a consistent pace and you repeatedly start and stop.

When I go trail running, I typically bring my dog along. Much of the time, I’ve got her on a 30 foot long leash. And quite often I find myself stopping for a few seconds here and there along with her.

When we get in a groove, we run more or less at my usual easy pace (~9:00 to 10:00 min/mile on the trails). But it’s not uncommon for us to average 11:00 to 12:00 min/mile for some of our trail miles.

I find that this tends to confuse the algorithm, and it just thinks that I’m running a lot slower than usual. And, to be fair, I am. But it’s not because of a physical limitation like fatigue. It’s because of my dog. I feel great.

Recently, I’ve actually turned off the VO2 max feature for trail running. Now, I no longer get the performance condition alerts on trail runs – which would almost always be negative.

Bad Heart Rate Data

One final issue is heart rate data. Any algorithm is only as good as the data you feed it. Performance condition is no different.

Imagine for a second that you’re running along at a moderate clip, but all of a sudden your watch’s optical heart rate monitor locks onto your cadence. One minute, your heart rate is 150bpm. The next, it’s 180. And it stays there, despite the fact that you haven’t sped up.

If you’re looking at the world through the lens of the algorithm, there’s only one logical conclusion. You’re suddenly sucking wind, and you are feeling really bad.

So from that perspective, it’s not surprising that bad heart rate data would mess up a metric like performance condition. But it is frustrating, and if you don’t have reliable heart rate data it renders the whole thing pretty pointless.

This is a good reason to buy a chest strap heart rate monitor, like the HRM Dual.

So How Should You Use Performance Condition?

As long as you keep in mind the limitations of the metric, performance condition is a good way to run a spot check on how ready you are for a workout.

On days that I’m recovering and going out for an easy run, I don’t really bother with or care about performance condition. But if I notice that it’s low, I may remind myself to ease up on the pace and resist the temptation to speed up.

But, on a day that I’m going to have a hard workout, I’ll check my watch during my warm up. If I’m not at a neutral or positive performance condition for the day, I’ll run a quick mental check of what might be wrong. Am I still fatigued? Am I getting sick? Or is there just a quirk in the data that I should ignore?

I usually do a mental check of how I’m feeling during my first mile or two of a run, anyway. But this provides a bit of objectivity to an otherwise subjective measurement of perceived effort.

I’m curious – how useful (or not) do you find performance condition? Leave a comment below and let me know.

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How Garmin Performance Condition Works: What You Need to Know

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