I am, personally, a reluctant tracker. I deeply dislike logging what I eat and do. My Wristy Overlord (aka Apple Watch) takes some of the calculating away and I have a trusty app (LifeSum. I use the free version, which does everything I want.) that figures out the calories in what I eat. I am only willing to do this much because, unfortunately, it works to keep me meeting my health and fitness goals. Given my general reluctance, it should carry some weight that I’m seriously considering tracking one more variable: heart rate variability.
This metric is the kind that is only worth tracking with wearable fitness trackers. I know Apple Health and Samsung’s version both calculate it, but my Fitbit knowledge is not up to date. It is not so important that anybody who doesn’t already use a tracker should rush out and buy one, but, as I am about to explain, I think it adds something useful to our toolbox.
Heart rate variability is pretty much exactly what it sounds like. It’s measured in milliseconds and it correlates with cardio fitness. The higher our heart rate variability is, in general, the more fit we are. However, it fluctuates from day to day, so it is also a good indicator for how ready we are to do a difficult workout.
A note here on the reliability of data from wearable fitness trackers: they are not usually as good as the big expensive kinds that hospitals use because hospitals don’t need to wear their equipment on their wrists. However, the wristy overlords are pretty internally consistent, so we can still use them to measure progress. It’s like using an idiosyncratic tape measure; as long as we use the same one every time, we can still see what has changed and how much, even if we’re measuring in Bigfoot feet or heptimeters.
The natural movement in heart rate variability plus the nature of fitness tracker measures means that step one in using wristy overlords to help us tailor our workouts is a boring and frustrating one: we have to get a baseline. To do this, we need to look at the data at the same time of day every day for at least a week and take the average. That’s not very hard, but the thing is that we have to do it without changing what we are doing. So those of us who are about to embark on a whole getting-in-shape journey need to spend a week eating and moving the old way to get the baseline before jumping on that new treadmill or weight lifting habit.
Then, with our baseline data in hand, we can get to work. We still need to look at the number daily at more or less the same time (first thing in the morning is best). Then we compare it to our baseline average. If the number is significantly lower than our average, it is likely that we are not sufficiently recovered from our last workout and should take it relatively easy (swap the weights for yoga, do the flat run instead of the hill workout, etc.). If we’re at or above our baseline, we can feel confident that we can handle the tough stuff.
This may be more than any of us really wants to deal with. That is all right. We can use subjective assessments (I am still really tired and sore from that workout on Saturday, so I’d like to go easier today…) to choose what we do today instead. I am just a little excited to find something that measures recovery. In other words, I intend to experiment and see what happens.
