Hi,

I think that the most important tech development for training theory in the last few years is the prevalence of arm band heart rate monitors. I personally use the Coros Heart Rate Monitor, which you can find for $79 here (it pairs to any watch brand and/or phone). 

If you look at any major marathon finish line, you’ll see pro after pro with an arm band. They have had almost full adoption, like disc brakes in cycling. Let’s break down the rationale of 3 different heart rate monitoring techniques:

1. Chest Strap: the gold standard for accuracy, measuring electrical impulses. I compare them to old rim brakes, because their accuracy advantages are offset by the logistical hurdle of getting them on and the potential breathing constriction of keeping them on, like how rim brakes are lighter but you might not stop in the rain.

2. Arm Band: these use optical readings, which can be lower accuracy for very short efforts, but that is not when heart rate is useful anyway. Athletes love wearing them too! If you walk into the club with an arm band tan line, they let you take over the DJ booth.

3. Wrist Readings: watches use optical readings as well, but wrist vasculature is much worse for accurate data. In fact, I think the data is relatively useless for runners (if an athlete sends me wrist-based data for heart rate zone analysis, I ask them to get better data and add a Patreon payment for my aneurysm treatment). To continue the bike brake analogy, wrist-based HR during training is like pulling a Fred Flintstone and trying to stop with your feet.

Arm bands entered the scene and made heart rate monitoring easy and repeatable (particularly for runners). And I think that has revolutionized how we develop training theory. Now, it’s incredibly easy to get a good feel for training zones, especially zone 2. 

When I stepped up to 100 mile races, the conventional wisdom was that athletes rarely had strong debuts, especially athletes like me who had never really excelled at longer races. I was aware of that wisdom, and I secretly thought I was going to crash and burn. How the heck do you pace these distances?

I decided to use heart rate, determining my zones from field tests (I wrote about that here). I rode the edge at the top end of Z2, which turned 100 miles into a simple math equation. High-carb made that breakthrough physically possible, and heart rate is the only reason I was able to let my physiology shine when I stepped into the unknown.

Heart rate excels as a method to constantly recalibrate your training zones over time. If you know your Z2, and you develop associations for how you adapt to different types of stresses, you can give your “feel” a quantitative edge. Eventually, you’ll be able to look down at your heart rate and be able to guess it to within a few beats. 

When heart rate and feel reach alignment, you can train on vibes, but with data to give you confidence. Over time, vibes and data can even become synonyms--to me, that’s a type of athletic nirvana.

Get one here!

- David.