Do you even track glucose bro?

We’re kicking off a new series on the blog called Coaching Hat, where I answer a specific training-related question while detailing the thought process that got me to the answer.

One question I’ve heard with greater frequency is some variation of this: Should I start tracking “_“?

The blank to be filled in is usually a new health/fitness metric. Here are a few that come to mind. Should I track my:

1. Sleep
2. “Recovery”
3. Continuous glucose
4. Heart rate variability
5. Muscle oxygen saturation
6. Sweat concentration

Undoubtedly, the list above will continue to grow in the upcoming years.

What Is Worth Tracking?

So what metrics are worth tracking for those interested in optimizing health and cycling performance?

My thought process for answering the “Should I track __” question begins with this passage I read in the 2016 book Deep Work by Cal Newport.

…all activities, regardless of their importance, consume your same limited store of time and attention. If you service low-impact activities, therefore, you’re taking away time you could be spending on higher-impact activities. It’s a zero-sum game.

Cal Newport

When choosing to ditch a service like Facebook or Twitter, Newport says: “to abandon a network tool…is not to miss out on its potential small benefits, but is instead to get more out of the activities you already know to yield large benefits.”

The takeaway is clear. Attention is a limited resource. It can’t be manufactured, only channeled. Every fitness technology you engage with forces you to choose what else you’ll give less attention to.

“Does this metric/technology inspire action or provide entertainment“?

Of course, most technology is fun to engage with, but if it doesn’t inspire action, we need to be honest and call it what it is: fitness entertainment that draws on our limited resources to take action to improve.

Let’s choose three metrics from the list above and run them through our action vs. entertainment framework.

Sleep tracking

Let’s assume whatever sleep-tracking technology you’re using can accurately measure the quantity and quality of your sleep. Should you track your sleep?

By now, most athletes have some knowledge of good “sleep hygiene.” So the question becomes, “assuming your sleep tracking reveals poor sleep, what would you do to change your sleep habits”?

OK, so hang on; if you already know what type of behavior change is needed to improve your sleep quality, why not skip the attentional cost of sleep tracking, and jump straight to changing your behavior?

In other words, if you feel sleep tracking will help you modify your behavior, it may offer you some value; otherwise, spend your time and energy directly changing your behavior rather than investing it in a technology that is likely to tell you what you already know.

Continuous glucose

One of the newer metrics to market, my first thought when evaluating continuous glucose monitors (CGMs), is “what does your current nutrition strategy look like?”

In short, decades of research have contributed to current guidelines for carbohydrate fueling during exercise. You can dig into those guidelines in detail in our Carbohydrate Fueling Guide.

Before considering the financial and attentional cost of continuously monitoring your blood glucose, how closely does your current nutrition strategy align with the high carbohydrate availability approach to fueling?

Back to author Cal Newport’s point on the zero-sum nature of attention. CBG data doesn’t come for free; it comes at the expense of another variable in your training. If that variable is planning and preparing higher quality food in life and training, then the expense of the technology vastly outweighs its marginal (at best) benefit.

Heart Rate Variability (HRV)

Proponents of HRV promise everything from an improved understanding of recovery to an enhanced ability to program training in “real-time.”

Without wading into the weeds of HRV, let’s assume it offers an affordable method to understand your recovery more accurately; should you track it?

Here are a few follow-up questions. Would you not train if your HRV value said you were fatigued? Would you choose to train harder if your HRV value said you were well-rested?

As a coach, it’s hard to imagine a world in which an HRV value would offer better guidance or retrospective analysis into fatigue than tracking RPE or some other subjective measure of training readiness.

Perhaps for a particular athlete, HRV offers an “objective” hard stop in training. A respected guard rail to say, “now is the time you must rest.” In this case, the attentional expense paid to track HRV daily might be worth it.

But most athletes are better served by improving the skill of understanding what it feels like to train hard, to be fatigued, and what contributes to their best days on the bike.

Do you have a training-related question you’d like me to dig into? Shoot me an email, and we may discuss it further in our next Coaching Hat post.