74. Your GPS Watch Is Lying to You
Your GPS watch gives you pace, distance, heart rate, location, and more data than you could ever need during an ultra. But what happens when those numbers aren’t as accurate as you think they are, or when your brain interprets them in a way that sends you straight into panic?
In this episode, I’m exploring why your GPS watch isn’t an infallible source of truth and why more data doesn’t necessarily lead to better decisions on race day. I show you where inaccuracies can creep into your watch data, how your brain turns neutral numbers into potential threats, and why reacting to those numbers without questioning them costs so many ultra runners their confidence, race goals, and even their finish.
Learn how to take back control of your race data this week by understanding what your watch can and can’t tell you, and deciding which numbers are actually useful. I show you how to use your watch to help you make smart decisions in your race, so you can stay calm under pressure, and trust yourself (not the tech!) to have the final say.
My 1:1 Mental Mastery Coaching for Ultrarunners is a six-month coaching program where we build the mental skills experienced ultrarunners use to handle difficult races well. Schedule a consult call to learn more here.
What You’ll Learn from this Episode:
Why the numbers on your GPS watch aren’t always as accurate as they seem.
How reacting to inaccurate or misinterpreted numbers can affect your race.
Why having more data available doesn’t necessarily help you make better decisions.
How to decide which watch metrics are actually useful to you as an ultra runner.
How to use your GPS watch as a tool while keeping yourself in charge of your race decisions.
Why self-trust matters more as an ultra runner than any number your watch can give you.
Listen to the Full Episode:
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Full Episode Transcript:
Welcome to Unstoppable Ultra Runner, the podcast for ultra runners who refuse to let anything hold them back. I’m your host, Susan Donnelly, veteran of over 150 100-mile races, and a coach who helps runners like you break through mental roadblocks, push past doubt, and run with confidence. Let’s go.
Welcome to episode 74. How are you all doing? How's your summer been? You have any races planned this fall? I actually do. I have two races coming up. I'm still recovering from hip replacement surgery, so I'll be walking them, but I'm up to 15 miles in the mountains. Slow miles, but mountain miles all the same, and I am so happy to be able to get back there.
My last race, just for perspective, was 100 miles at Across the Years in Arizona 10 months ago. So I'm building muscle back at the same time as the hip is recovering. The first race of the two that is up is a race for the ages or ARFTA in Tennessee. And for those who don't know it, this is a fixed time race where if you're over 40, like I am, you get your age in hours to do however many miles you want. So I have 63 glorious hours to do whatever mileage I want, and actually, I think this episode may air that week.
Then, I got to head home, do a quick turnaround because the following weekend is a marathon at the Superior Fall Races in Minnesota. I've run the 100 there, I think 22 times. I am tied for the most finishes there with my good friend Stewart. And I was the first female there a couple times back in the day, and I've got masters awards and grand masters awards there. I love that race. It was my first 100.
And I am nowhere near technical 100-mile shape right now, but I think I might be able to do the marathon. I might be able to pull that off. It's a gamble, but I'm excited to try it and see what I can do. I have zero to lose. So these two races are truly experiments, and I am really excited and curious to see how they go.
Okay. Today's episode gets the engineer in me totally geeked up and excited. I am so ready for this one because we're going to talk tech in a way that's going to be super valuable to you. Starting with a story. This story takes place years ago at Mountain Mist 50K in Alabama. It takes place in January, and it has taken place for the past 32 years. I've run it 15 times over the years, not consecutively, but 15 times over the years, and it was one of the first ultras in the Southern US.
So really, it was like the only thing going in January in the Southeast back then. So all the ultra runners in the Southeast used to travel to it from wherever they were every year. It was like an annual reunion. We all knew each other, and it was a reunion and the start of the racing year for us. Anyway, one year in this race, I was somewhere in the middle miles, and by then all the runners had thinned out. It wasn't as many runners as it is now. All the runners had thinned out, and there's nobody behind me and there's only one woman in sight ahead of me.
And I know by elapsed time on my watch and a little bit by course memory, except the brown woods in January all kind of look the same, that I will be coming into an aid station pretty soon. Sometime in the next 10 minutes or so. In this race, you run a course around the top of a mountain, horizontally, more or less, at the same elevation. So you're always weaving in and out of what we in the South call hollows or hollers. And it could be the next hollow or the one after that, but the aid station's going to be soon. And I'm not worried. I'll get there when I get there.
So I'm running okay. This is the middle miles. And I come up behind this woman and I tell her I'm passing, and after I pass, she asks if I know where the aid station is. And I say soon, and she asks, are you sure? And I say, yes, it's pretty soon. She asks, are you certain that we're on course? Which wasn't the question I was expecting. So I ask why, and she says in a panicked voice that her watch says it should be behind us, that we've passed it.
So she's freaking out that we're lost, and she's thinking about calling somebody to come get her, even though we're nowhere near a road at the time. She thinks I'm wrong or she doesn't trust me that it's right around the corner and she wants to turn around and go back, except she doesn't know how far back to go and she worries that she'll get even more lost going back.
So I convince her to trust me that we're near the aid station, that we'll get there and to have patience and stick with me because I've done it before. And sure enough, we come around one of the very next hollows and there is the aid station. But what I discovered in talking with her is that she saw her watch as infallible, the absolute truth of the world. So whatever it said, even if that contradicted what she saw with her own eyes, what it said had to be right. In her mind, the watch was right. Therefore, if there was a difference of opinion, she had to be the one that was wrong.
And since then, I have seen that same thing repeated over and over countless times in races. The aid station isn't where it's supposed to be or the advertised mileage is wrong. And I've also seen runners drop because the watch numbers say that there's no way they can make it to the next aid station before cutoff. Now, what do these scenarios have in common? What they have in common is that all the runners were reacting to what their watch was telling them and it was costing them a race in one way or another, in either surrendering their confidence, their goal, or their finish.
So if you wear a GPS smartwatch, you have tons of data available to you, an almost infinite supply. And when you're doing a big, important event like an ultra that you've trained for months to run and only get to run once a year, and maybe it's a lottery race, you want all the data you can get. Because all the data feels important. It's information about your running that you can't get any other way, or so that's what your brain tells you.
You want to make the fastest, best in-the-moment decisions you can in a race. And the more data you have, it seems like the better and faster decisions you'll be able to make. You won't have to wait until an aid station where you can, maybe, maybe get the information you need. You'll have it with you, on you at all times, at your fingertips. More data equals better decisions.
That's the logic. And I used to see this all the time at my work as an engineer. Numbers don't lie, and the more of them you have, the better decisions you can make. So we need to get all of the numbers we can. I used to call it data worship. But what often happens in a race is that you struggle to make your best decisions anyway. Because the watch doesn't just say, yes, you can make it to the next aid station, you're doing great, keep going. It gives you numbers that you have to interpret and decide what they mean.
The numbers from the watch have to go through your brain to have any meaning. They're just numbers on your watch. They don't have any meaning until your brain decides what they mean. And in a race, when you're under time pressure, possibly a little stressed about how it's going, trying to stay on top of eating and drinking and you're tired, interpreting that number is where things can go wrong.
Because you're probably going to interpret the numbers negatively to mean that you're going slower than you wanted and you won't hit your goal. And even if you ask a stranger who seems like they know what they're doing for their opinion, like that woman at Mist did with me, you'll still likely stick with that negative interpretation over anything I say. Because numbers don't lie, except they do. At least, the numbers do some lying and your brain does some too.
The numbers come from your watch, and without going as totally engineer on you as I want to, watches are made by humans and human-made machines and they get information from human-made satellites flying around in the sky. So as amazing as your watch is, and it is truly amazing, the watch, the software that creates the numbers and the satellites all contain a tiny bit of error, each one of them, and that adds up.
Sometimes more than others. Those numbers aren't as infallibly accurate as you think. They don't intend to, but they do some lying. Human brains, on the other hand, are wired to look for threats in order to keep you alive. That's what brains do, even more so in a race where you're already on heightened alert for threats to your race. So your brain does its own kind of lying too. It'll lie on the side of caution and tell you that the number you're looking at on your watch is bad news.
Your brain doesn't see a number, it sees a potential threat. Seeing that you're behind goal pace right now doesn't register as data that you need to act on, it registers as danger. And a brain that thinks it's in danger doesn't see things clearly. It takes you straight to worst-case scenario, which means you're likely to interpret the number that you're looking at on your watch as a problem that you need to do something about now because you're in a race.
So you panic and react like the woman at Mountain Mist, or like the runner dropping. You assume you took a wrong turn, or you push hard when you don't need to and trash yourself. Or you don't push hard when you do need to because it doesn't seem like there's any way you're going to make it to the next aid station on time, so what's the point? You misestimate your hydrating because the number you're reacting to on your watch doesn't match what's actually true on the course.
And you can't sustain being wound up like that, trying to wipes you out. So you make decisions that you regret later, like the runner who dropped. And ultimately, the way you use the numbers negatively impacts your race. You end up making bad decisions. The solution to this is to get in control of your numbers. Get in control of how you understand and use watch data in the race. Turn it around so the tool and the numbers aren't in charge. You are. That means understanding your watch and deciding what you want from it.
For example, do you really want to know a race prediction time in the race? And do you know how your watch is calculating that? Do you want to make decisions on that? Like how are you going to use that number in the race? What decisions are you going to make with it? And do you like your reason for having that number? When I say understand your watch, I mean understand when you choose for it to read a number, what that number means. Like what does the watch mean by training status or endurance score?
It might not be what you mean or what you think it means. What does the watch mean with that number? How is it calculating it? And if you know how it's calculating it, is that valuable information to you and why? Read the manual. And most important, understand what your watch can't do for you. It doesn't guarantee the absolute accuracy or completeness of running, mapping, or fitness data. So metrics like GPS tracks, pace, heart rate accuracy, and training status calculations are estimations rather than certified measurements.
Yes, even GPS tracks. GPS data seems like a fact, but it's actually not supposed to be used for precise measurement of direction, distance, location, or topography. The map data isn't guaranteed by the manufacturers. Okay? And any GPS device can fail or give you inaccurate data. And it's not just tree cover. Out on a mountain course, your watch is trying to catch a signal from satellites way up in space, as many satellites as it can, which is not always optimal. And mountains get in the way of that signal just like trees do.
The signal can bounce off a ridge or a rock face before it reaches your watch, so the watch ends up guessing at where you are instead of knowing. And it's worse in terrain like at Mountain Mist, in that race, with narrow hollows and walls on both sides. Exactly where you need the number to be right, it might not be. So read the fine print. And once you know what the watch can and can't do, you've got to decide what you want from it.
And what I want you to do is constrain down to the essentials. Why? Because more data isn't better in a race. Too many numbers can quickly overwhelm you, so you freeze and can't make a decision under pressure. And too much data is noise that just gets in the way of you focusing on the data that actually is useful. I help clients make all these decisions before a race. Do you really need the pace in the current mile, or do you need overall pace?
Which one is more useful? And don't say both because you just don't know. Make a decision. And make those decisions now. The fewer essential numbers you're looking at, the better. Then, program your watch so those are the only ones you see in a race. So you don't get distracted with the other ones. You still need to constrain what the watch gives you so you don't have to sift through all the data clutter and risk getting distracted to find the number that you do want. So decide the essentials.
I have to be honest here that I don't wear a GPS smartwatch myself. I'm sharing what I see from the outside here, a pattern that I often help clients untangle and I want you to see it too. And it might not seem like mental mastery includes tech, but it does, because you use your mind to make decisions, including the decisions about how to use your watch to help you. And the decisions that you make about your watch data before the race shape the decisions you'll be able to make during the race.
Think of it this way. Anything that involves the mind, which is everything in ultra running, you use your mind for everything in ultra running, all the things that you're thinking and decisions you're making is all part of what I help clients master, including tech like this. And when you master something that seems as simple as the way you use your watch, it can profoundly change your races.
So three things: understand what your watch does and does not do, especially the accuracy of the numbers it gives you. And decide what numbers are essential to you in the race. And then, program your watch to give you only those so you don't get distracted by all the other numbers. And when you do, you'll have the numbers you need to make decisions, and you will know how to use them in real time under pressure, which gives you confidence.
You can make smarter decisions in real time. You'll be able to stay out of panic and overwhelm, which means you'll be better able to stay cool under pressure. And you're controlling one of the controllables instead of reacting to it, which means the tool isn't in charge of your data, you are. That's how to use your watch to make smart decisions in the race.
I think back to that day at Mist. I didn't need a watch to tell me the aid station was close. I knew how much time had elapsed from the last aid station and how many miles we had to go. I knew the course and I trusted my navigation, and I made a decision about what all of this meant. That's the part no watch can give you: the self-trust to decide what's true. Next time the watch tries to tell you what's true, remember, you get the final say.
All right, you all, that's this week's episode. Thanks for listening. And before you head off, if you're listening on Spotify, I've got a quick poll waiting for you just below the player. I'd love to know your answer, so take a second to vote before you go. And if you know someone who could use this episode, share it with them. It might be exactly what they need to hear. See you next week. Bye.
Thanks for listening to Unstoppable Ultra Runner. If you want more ultra talk, mindset tools, and strategies for running with confidence, visit www.susanidonnelly.com. This podcast receives production support from the team at Digital Freedom Productions. That’s it for today’s episode. See you next week.
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