How Your Watch Can Hurt (Or Help) Your Growth

Published August 10, 2021 08:05AM

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I think that there is one little sound that can undercut growth for many athletes. It’s sometimes accompanied by a light buzz as if it’s a vibrator for a mouse.

You glance down, a Pavlovian response learned over the years with GPS watches. It’s a mile split. You keep running, a bit uplifted or a bit deflated, waiting for a few minutes later when the mouse has another orgasm.

Over years of coaching, my co-coach/wife Megan and I have seen so many athletes grow to hate parts of the process, a large part stemming from that number that flashes up on their wrist. “You’re OK for now,” it says, or “You suck,” it screams, without having the first clue about what that means for adaptation and growth.

But it’s a number. And numbers don’t lie, right? So it’s damn near impossible to avoid falling into the trap of trusting it.

We ask our athletes to turn off the lap function on their watches. You can too. And don’t stop there. Go into “Settings” and take off pace as well. With all those numbers, your smartwatch may just be a dumbass. Have the main data screen show time, make yourself scroll to another data screen to see distance, and you can glance at pace after the fact if you need to.

It all gets back to paying attention to what matters, and ignoring what doesn’t. And here’s the big takeaway: real-time splits may actually be hindering physiological adaptation processes. What seems like good data is actually obscuring what matters (effort, feel, presence) in favor of a false sense of certainty. When noise is presented as signal on a watch face, many athletes end up acting against their own interests.

And let’s go with a big, sexy one: the power hour. An hour tempo, on trails, finishing hard.

At mile 1, you get a split. This mouse must have read some tantric guidebooks. It says 7:15.

If that number aligns with effort-based expectations, an athlete may feel temporarily satisfied.

But if that number has some misalignment, crap can start hitting the fan. Stress hormone cortisol may spike with the stress response from the letdown, dopamine levels could decrease, motivation along with it. The rest of the workout may have slightly higher physiological hurdles to clear. And those hurdles will be there for no good reason.

GPS watches are inaccurate at the margins where the body adapts to stimuli. Studies find anywhere from 1% to 6% margin of error on most GPS watches, with variance based on location. Even at the low end of that range, that 7:15 could be a 7:10 or a 7:20. Athletes will train for months to drop their pace 10 second per mile. The data errors may be overwhelming the underlying physiological changes. Sometimes, the errors are far greater, like in “GPS dead zones” with lots of trees or turns. Those erros may not be precise, either, with seemingly random variation around the true value.

Even if the watch measures perfectly, daily variability in things like temperature, recovery status, and stress cause variation that can be greater than 10% for the same effort. That 7:15 could be worth a 6:30 on a brutally hot day, or after a night up with a newborn. That’s obvious, and it’s something we all know intuitively. But the watch doesn’t know that. It just spits out a number, oblivious to the obvious.

And perhaps most importantly: the cells don’t care.

Our brains like to grasp onto numbers as a way to add certainty to an uncertain process. But at best, the instant pace readings are a proxy variable for what the cells and systems of our body are actually experiencing. Mitochondria in muscle fibers don’t give a single crap about whether we’re running 7:15 pace or something a bit different. They care about the chemical context–the fatigue byproducts, the enzymes, the protein expression, none of which are all that affected by minor pace variations. The same applies to adaptation post-run, with stress and emotional state actively influencing how the body interprets the same stimulus.

Paying excessive attention to splits can slowly take an athlete out of the moment with an activity, leading them to miss the actual signal we care about. That power hour sure is impressive at 6:59 pace! So they push harder, trying to get it under that threshold, continuing the process on subsequent days, overstressing themselves needlessly. I think GPS watches contribute to more injuries than anything other than failure to eat enough food.

The problem is worst of all on easy days. Our brains almost always default to wanting “GPS porn,” even when what we need is “GPS read-a-book-and-sip-chamomile-tea.” When I say that easy is not a pace, it’s an effort, what I mean is that the cells don’t care if 8 minute miles should be easy for you based on your expected marathon pace. They care about how you feel, which is incorporating thousands of chemical signals to give you more information than a smart watch ever could.

So that’s the big message: pay attention to how you feel.

In track races and road marathons, where athletes need to dial in the specific biomechanical and metabolic demands of a given pace, the watch can play a bigger role in aligning feel with output in workouts (though beware of that inaccuracy problem, with measured courses or tracks always being best for key pace-based efforts). If you aren’t doing a race like that, then pace-peeking risks scratching an ego itch rather than an information itch. And that ego monster can never be satisfied. Many times, the ego monster wants us to feel like a piece of crap to justify its own existence.

If you ever find yourself getting haunted by that ego monster, even for a few splits, it’s OK to try something new. Megan and I suggest making your smart watch into a dumb watch with benefits. Change the display screens and notifications to remove pace availability unless you’re doing a specific-pace run in marathon or track training. Don’t lap out your efforts unless you have a coach that wants to act on that information. Even keep distance at least one click away so you aren’t doing compulsive mid-run math. You can upload the run afterward for analysis by yourself or a coach, but let the run just be running, not a mix of a moving math problem and inefficient therapy session.

It would use all the same technology as the rest of the watch companies, with one key difference. Every time an athlete reaches a new split or hits the lap button, it gives an affirmation instead of a number.

That’s a more loving and silly approach, sure. But I’d also argue that it’s a more honest appraisal of the science of pace and adaptation, since it’s not trying to oversell precision, but it’s still 100% accurate.