Wearables. It’s the new fad word just like functional exercise, holistic living, and evidence-based..
But like most things that come in ‘fads,’ the true benefit and meaning of them often remains blurry, hidden behind a swarm of misinformation and misunderstanding.
When we say “wearable” or “wearable device” that’s the term for some kind of fitness tracker you wear on your body. The most popular wearable fitness devices are Fitbits, Whoop Bands, and Oura Rings. You can even throw devices like Apple Watches into that mix.
And while they each have their drawback and benefits, they’re all worthless if you don’t do anything with the data they give you.
Whether you already have a wearable device or just got one for the holidays, there are two metrics that are the most misunderstood.
Once you know what these metrics mean, you’ll be able to actually use the data to make meaningful change. After all, all the data in the world is completely useless if you don’t use it to spur changes that lead to progress. But at the same time, if you try to implement everything your wearable device is telling you at once, you’re going to be overwhelmed.
So start with these metrics. They’re not only some of the more nebulous metrics, they’re also, once you understand them, some of the most powerful. And, nearly every wearable device tracks these two metrics.
Heart Rate Variability, or HRV, is the most effective measure of autonomic nervous system stress. If this system is stressed it will show immediately. But what exactly is HRV?
Heart rate variability, as the name implies, is the variance of the time in between your heartbeats. That may sound a bit nebulous, so let’s break it down.
Two people could have the exact same average heart rate, but one could have a much higher variability between the heartbeats. The latter has more fluctuation (variability) in their heart rate, so they have a higher HRV even if it averages out to the same average heart rate.
We call the time in between heartbeats is called an RR interval (because the R-phase of a heartbeat is what causes the spike on an electrocardiogram (EKG)).
In this made-up example, the RR intervals are 67 milliseconds apart. Thus, we say the HRV is 67.
A higher HRV means your body is responding aptly to changes your body demands. If you have a high HRV, that means that as soon as you need to sprint, your heart rate can increase as quickly as possible in response. Then, when you’re resting, it will recover down to a resting heart rate much quicker, also. Basically, it means your heart is doing its job exceptionally well.
A low HRV, then, means the opposite. It means when you sprint it takes longer than normal for the heart rate to rise. That means your heart won’t be pumping the blood it needs to for optimal performance, even if only for a brief time. Likewise, your heart rate might come back down slower.
Generally, more fit people (we mean cardio fit) have a higher baseline HRV. There can be some value in looking at that, but in the context of a wearable device, that doesn’t contain any information you can use to make changes on a day-to-day basis.
This means that on the day-to-day, HRV is one of the best measures of your recovery. If you have a higher HRV than you normally do, it means your body is responding effectively to the demands you put on it. That’s a signal that your body is recovered and ready to put on the gas.
But if the next day it’s lower, that means you’re in a recovery mode, and probably can’t train at your best.
If you wake up and your heart rate variability is much lower than normal, that’s a sign to ease off and recover, rather than push forward with a tough workout. Likewise, if your HRV was higher than normal, that’s the day to do a few extra sets in the gym.
Basically, the greater your HRV, the more “ready” your body is to perform at a high level.
I know David did a whole borderline dangerous sleep experiment, I’m talking about us mere mortals without insane sleep schedules here. So let’s put this anomaly to the side.
Whether we’re talking about sleeping more or sleeping deeper, sleep is the number 1 indicator of chronic illness prevention, longevity, focus, clarity, ability to optimize flow state, as well as just being an overall happier person. That’s right, better sleep is associated with just being happier.
By prioritizing sleep, you can take even your happiness to the next level. But we’re not talking about your standard “sleep eight hours” version of sleep your doctor tells you.
We’re talking about badass, innovative sleep that will revolutionize your routine and effectiveness. (Maybe we can make sleep cool again.) That starts by understanding some of the different phases of sleep.
We all have 90-minute sleep cycles, where we go from light to deep (slow-wave) to REM sleep. What’s unique to each of us however is how long we take to get into slow-wave and REM sleep.
REM sleep is the restorative sleep we enter into when we actually recover both physically and mentally. Some of it is genetic, sure, but we can all impact the speed in which we get into restorative sleep with some simple shifts to our nightly routine.
Your wearable device will tell you how much REM and deep (restorative) sleep you’re getting compared to light sleep. If your light sleep is greater than 60% of your total sleep time, then there needs to be an overhaul in your pre-bed habits. By improving your nightly routine, I’ve seen people increase their time of deep and REM sleep by as much as 40%.
And, this is all without sleeping more, but just by sleeping better.
I’m probably not going to say much you haven’t heard before. You should have a consistent sleep-wake time, turn off electronics well before bed, and unwind from exercise hours before you hit the sack.
So I won’t lecture you on that. This is where your wearable device comes in to do the lecturing for me. If you’re looking at your wearable for sleep data and you notice you’re lacking REM or deep sleep, start by making one shift in your nightly routine. Maybe the last twenty minutes before you sleep you read a book instead of watching TV. Your wearable will tell you how effective that is. You can use your wearable to guide you and measure the effectiveness of the changes you’re making.
That, after all, is what they’re for.
Data is useless if you don’t do anything with it. And wearables today are telling us more and more (and the tech will only get better of course). So, my last piece of advice to you and not to change too much at once. Use the data from your wearable device to make just one change.
Maybe you’ll look at the HRV and do an extra set today because you know your recovery is great. Or, you can improve your REM sleep by relaxing for 30 minutes before bed. Whatever change you want to make, just make one. Then, once it’s a habit, go back to your wearable device and find another area where the data is telling you you can improve.
While wearable devices like Fitbits, Whoop Bands, Oura rings, and more are getting more and more attention, I believe they won’t fade like other fitness fads of the past. And that’s because they really do give the user valuable data. But, that data will only be helpful if you actually use it. So whether you start looking at HRV or sleep data to start making meaningful change, choose something from your wearable device to start making change, and therefore, progress.