This morning, 57.7 percent of me was water. My resting heart rate was 57. And I averaged 184 steps per minute on my run.
Fitness tracking and wearables are a huge market, and you might even have a device on your holiday wish-list. Pretty likely when I mentioned resting HR, you thought about checking yours on the device on your wrist.
I’m a data junkie: most of my training is heart-rate based, and I have a Garmin Forerunner 35 plus a Garmin Index Smart Scale. But a lot of that data is logged, recorded, archived … and never used for anything.
So what the heck do all these numbers mean, and which ones matter? I talked to two guys named Matt who helped me sort through the data I’m collecting to help make me and YOU better runners.
Matt Ebersole is the coach of Personal Best Training, based in Indianapolis but with clients across the country. He’s been coaching for 25 years, and works with runners of all levels, from 6-hour marathoners to Olympic Trials Qualifiers. He also has the dubious distinction of being my coach. For this piece, we’re just going to call him “Coach”.
I also talked to Matt Fitzgerald, author of “How Bad Do You Want It” and “80/20 Running,” among other books and articles. He also coaches and writes for a number of running and triathlon publications. He gets to be “Matt”.
“I believe that many of the health and fitness metrics that runners are now able to monitor with wearables, apps, and other technologies CAN be useful,” Matt said, “Whether they actually ARE useful depends on how they are used.”
If you wear a FitBit or other activity tracker, you probably have this data. If you record it frequently, it can be a great tool. An uptick in your resting heart rate can indicate you’re not fully recovered, or that you’re overtraining.
“But as with most numbers, people don’t pay attention to it until something is wrong,” Coach said.
Matt said his favorite app for monitoring training stress and recovery status is HRV4, which measures heart rate variability rather than just resting heart rate. The app uses the camera on your phone to measure your heart rate, so no sensors or straps are needed. (Current generation phones include both a camera and a light emitting diode, which can be used for reflection based bio-optical imaging. The technique is called photoplethysmography, or PPG.)
“What distinguishes it from similar offerings is that it is supported by reliable guidance on how to use the information you’re gathering about your body in order to train more effectively,” Matt said.
Coach said knowing your iron levels, both ferritin and hemocrit, is really useful especially for female runners. Again, you need baseline data to make the most of this for comparison.
“I have some women who train well at 35-40 [nanograms per milliter (ng/ml)], but some who are over 100,” Coach said. “It makes me wonder what those women could do if they were at 100, too, though.”
This wide range points to the need to get your levels checked when things are going well — during a recovery phase, for example. Then, if you’re feeling run down in a period of heavy training, a check of your iron levels can be compared to past data.
“Ideally, we’d track that every two weeks or once a month,” he said. Obviously that’s not feasible for most people, but worthy of routine checking.
Measured in steps per minute, cadence is a way to measure the efficiency of your form. But before we say anything else about it, know this: any changes to your cadence should come from strength training and stretching — not by just trying to take more steps.
While it varies by person and pace, around 180 steps per minute is a general target. More and more running watches track cadence, but it’s also pretty easy to do with just a timer. For 30 seconds, count the number of steps you take on one foot, then multiply by four. If you’re bored on the treadmill, that’s a great place to check your cadence, and you can see how it increases at higher speeds.
Coach said a dip in cadence can be a predictor of injury, because it can show a runner is slipping back into old habits. Fewer steps per minute is typically an indicator of overstriding, and also increases impact forces on your legs and decreases forward momentum.
Matt is more hesitant. “Research has consistently shown that virtually any attempt to increase or decrease one’s cadence from what is natural worsens running economy. That’s because runners naturally adopt the cadence that is most efficient for them.” Cadence can change beneficially — “but it has to happen naturally as part of the subtle stride evolution that unfolds as runners keep running.”
If you’re really interested in understanding biomechanics and injury prevention, pick up a copy of Jay Dicharry’s “Anatomy for Runners.” It’s the one my physical therapist uses in her work, and it has a place on my nightstand.
Salty Running is very conscientious about discussing weight, and running isn’t a thing we do to be thinner around here. However, not weighing enough can hinder your training. Coach said one of his runners always runs poorly when she drops under a certain weight. As soon as she tells him she’s struggling, that’s what he has her check.
He also shared what I think is a genius, forehead-smacking idea: set your scale’s “0” to an arbitrary number — it’s not your actual weight that matters, it’s the trends in increases and decreases. Some fluctuation is normal, but trends one way or the other can explain other training issues, injuries, or illnesses.
I know I should get 8-9 hours of sleep per night, but if I don’t use an alarm that shows how many hours I have until it’s time to wake up, I won’t get enough. Same for having it logged via my Garmin. It just takes staying up a little later and getting up a little earlier and suddenly it’s Saturday long run day and I’ve had six hours of sleep the two nights before.
So for me, sleep tracking is a reliable way I can make sure I’m logging enough hours. It can also point to issues you might be having, like if you wake up frequently.
Remember, sleep is when your body recovers from training and fitness gains are made. If you’re not sleeping adequately, your training may be for naught. Sleep deficit can also weaken your immune system.
And two things that don’t matter at all
- Pace on easy days. Coach said some runners focus on this as a measure of fitness — the faster you can run on easy days, the more fit you are. He recommends using heart rate as a key indicator for easy days and not worrying about pace at all.
- GPS and the Strava effect. To some extent, this phenomenon has existed as long as we’ve had any sort of watch. “I’ve even found myself doing this coming back from knee surgery,” Coach said. “I look down at my watch and feel like I have to speed up or I’m going to kill my average pace.” Accept it: nobody cares. (But it’s okay if you run three laps around the parking lot so you finish on a round number. No shame in that game!)
No matter what metrics you track, the most important part to remember is to be consistent and to have a baseline. Without a lot of data and without a measure of what your “normal” is, all of these metrics are much less reliable indicators of, well, anything.
What metrics do you track? Which ones do you find the most useful?