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June 17, 2022


Wearables are watches, rings, and other devices used to track a variety of measurables like daily steps, calories burned, sleep, and heart rate.

Spoiler alert: you shouldn’t put too much emphasis on wearables.

This article is about a month in the making. I started it weeks ago, then waited to finish it after attending the Perform Better Summit where I listened to Brandon Marcello, a human performance strategist, discuss wearables. One of his roles is to test and recommend wearables for the military and National Basketball Association. I’ll be citing some of his comments here.

It’s most important to note that ALL wearables have a degree of error, some more than others. If you use a wearable, the most important thing you can do is look at trends up or down instead of fixating on a number.

Here, I will break down the good, the bad, and the ugly of common metrics.

Energy Expenditure

I’ve known for a while that you shouldn’t rely on the energy expenditure (the amount of calories you burn in a day) shown on wearables because there are so many individual factors that contribute to this actual number, like your muscle mass, your metabolism, etc. I’ve seen many people fixate on this number and use it to determine the amount they eat each day. Oftentimes, they are way off. If you’re interested in a longer study about wearables and energy expenditure, you can read more HERE. But, my advice would be not to pay much attention to your daily “burn.”

Daily Steps

There are many wearables that do a decent job of tracking daily steps. If you were to wear several of them at the same time to compare, they would all be a bit different, but generally, they estimate steps pretty well. So, I'd recommend paying attention to this number and aiming for 10,000 steps per day.


In terms of sleep, some devices do a better job than others. No wearable can actually tell you the accurate amount of REM and deep sleep that you get - it takes more advanced testing to gauge these. Each wearables company has its own algorithm that estimates your sleep based on factors like your movement and heart rate.

Daily Strain or Readiness

Many wearables will give advice on how well you are recovered and suggest when you should take a rest day. This advice isn’t always accurate. You know your body and, if you’re feeling great, you can oftentimes ignore when your wearable tells you to rest. Or, if it tells you that you’re great, but you’re not feeling great, go ahead and take that rest day. Again, look for trends up and down. If most days your readiness is at a nine and it drops to a five, then maybe it IS time for a rest day.


Heart rate variability, or HRV, is a shift in timing between heartbeats. Tracking it can tell you if you’re in mostly a parasympathetic or sympathetic state. If your wearable is on your wrist, HRV is not accurate, as the formula is derived from your pulse rate, not your heart rate. Again, look for trends.

Heart Rate

Unless you are wearing a chest strap paired with your wearable, your heart rate reading is not very accurate. So, don’t freak out if, during a workout, it seems super high. Go by feel. Or purchase a chest strap if tracking your heart rate is important to you.

According to Marcello, after testing all the wearables on the market (when I met him he had one on each arm plus a ring!), here are his best bets:

  • Overall: Apple Watch (but get a chest strap if you want accurate heart rate; he recommends a Garmin strap)
  • General Fitness/Steps: Fitbit Sense
  • Navigation: Garmin
  • Nighttime/Sleep: Oura Ring
  • Whoop: avoid. This device is popular in the fitness space now, but Brandon says it’s “the equivalent to the Magic 8 Ball.”

In summary, wearables aren’t a waste, so don’t go pitching yours in the garbage. They are OK as long as you understand their limitations. And, with technology moving so quickly, they are only going to improve.

Don’t get caught up in the numbers. Instead, look for trends up and down. This can inform your behaviors, habits, and choices.

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