top of page

Are fitness watch metrics helpful or unhelpful?

The improvements in technology for athletes continue to grow exponentially. (Yes, you are considered an athlete if you train at any level). Metrics measured by watches, chest strap monitors, and even phones take in and analyze an incredible amount of data. So much so that you may not even know what some of it means or how you can use this data to your advantage. We'll primarily talk about watches today, as that is one of the most common forms of data tracking in the world of training. Whether you have a Garmin, Apple Watch, Coros, FitBit, Polar, Suunto, or another type of wearable, it's likely claiming to identify your heart rate (HR), heart rate variability (HRV), sleep, sleep score, body battery, steps, and calories burned. Some might have a pulse oximeter, respiratory rate, or activity monitor.

HEART RATE (HR) The heart rate feature identifies how many beats per minute your heart beats. According to the Mayo Clinic, a "normal" resting heart rate is 60-100 bpm, but some highly trained individuals may be closer to 40 bpm. Other factors such as medications and stress can affect your heart rate, too. Why it might be helpful: HR is something you would potentially want to keep an eye on during strength and/or cardio workouts. We often use Heart Rate Zone training for cardio sessions within my 1:1 online coaching, as well as KATHLETICS Trail. Why it might not be helpful: Watch HR readings are not always accurate. The watch may be too loose or too tight to get an accurate reading. Also, some watches have a harder time reading heart rate if you have tattoos on your wrists. Going off of RPE (rate of perceived exertion) during exercise is likely a more reliable method. HEART RATE VARIABILITY (HRV) Heart rate variability is the time between each beat. HRV is used to help determine things like stress score and body battery. Why it might be helpful: Variability in HRV can help you identify if there are any underlying factors to how you're feeling such as high stress, low stress, strained, maintaining, or recovery training. Why it might not be helpful: If the watch isn't properly fitted, you may not get an accurate reading. If the watch isn't consistently warn, HRV status will have a hard time seeing patterns and adapting. SLEEP As we know, aiming for 7-9 hours of sleep per night is ideal. The sleep feature on watches identify your quantity of sleep. Why it might be helpful: Sleep trackers help you see patterns in the timing of your sleep (what time you go to bed, what time you wake up). It can also give you an idea of your light sleep, deep sleep, and REM sleep cycles. Why it might not be helpful: If your watch isn't properly fitted, it may not identify sleep or wake periods accurately. For example, it may not pick up when you were awake vs in a state of light sleep. SLEEP SCORE The sleep score considers both the quantity and the quality of sleep based on duration, heart rate, stress, and interruptions. Why it might be helpful: Your sleep score can help you see if your quantity and quality of sleep align. Just because you got 8 hours of sleep doesn't mean it was efficient or just because you got 6.5 hours of sleep doesn't mean it was inefficient. Sleep scores give you an idea of how restful or restless your sleep was. Why it might not helpful: Sleep scores may not properly display how well you slept. Just because your sleep score was a 72 doesn't mean you had poor sleep all around with poor recovery and just because your sleep score was a 98 doesn't mean you slept like a baby and are ready to take on any task. BODY BATTERY Body battery calculates by monitoring your activity and stress levels. Body battery can affect your energy levels, ability to problem solve, and regulation of emotions. Why it might be helpful: This feature can help you identify patterns regarding how your sleep, stress levels, and activity are affecting your recovery. Why it might not be helpful: Body battery may not depict how you actually feel. Just because your watch says you have a body battery of 65/100 doesn't mean you can't perform at your best mentally or physically today. On the other hand, just because it says you have a body battery of 100/100 doesn't mean you're not going to get tired today. STEPS Steps identify how many steps you take throughout the day. Some watches even have a feature that creates and adapts a step goal based on your average step count. For example, if you average 6,000 steps/day, your watch may suggest a goal for 7,000 steps/day and adapt to you. Why it might be helpful: Seeing the amount of steps you have taken daily may encourage you to increase or decrease your step count. For example, if at 3pm, you notice you have walked 2,500 steps, it may encourage you to take a walk. On the other hand, if you are training for a half marathon and notice your step count is already at 16,000 steps after your long run, it may encourage you to take it easy and recover for the remainder of the day. Why it might not be helpful: Step count may be skewed depending on how sensitive it is to movement. If you have a job that requires you to move your wrists frequently (i.e., a hair stylist), the watch may assume you are walking when you're not. Also, the watch may not pick up your movement at all. Fortunately, technology is enhancing, but keep this in mind. CALORIES BURNED Calories burned is a topic of discussion because as a consumer you would hope it provides insight as to how much food your body needs to be in a deficit, maintenance, or surplus phase. Why it might be helpful: This feature is not helpful. Why it might not be helpful: Calories burned is not helpful because it's not accurate, therefore does it help you achieve your goals of weight loss, weight gain, or body composition change. This data point alone does not identify how you're feeling, if you're energized, if you're tired or fatigued, or where you're at in your menstrual cycle (for those that applies to). I suggest taking inventory of your food intake first, then applying a slight deficit or slight surplus to your diet to see how your body adapts vs focusing on an inaccurate number of calories burned. Watch data is great data to have, but it doesn't necessarily mean it's the end-all be-all. When you read the data from your watch, I encourage you to ask yourself how you feel first. There are times when I wake up in the morning feeling excellent, I look at my sleep score and it's subpar. Or, there are times when I feel like my RPE is at a 9 while out of breath and my heart rate reads 95 bpm. Always ask yourself how you feel first. The watch is simply a tool in your toolbox.


Katharine Moustakes
Hey, friend!

I'm Katharine.

I'm a personal trainer, running coaching, and nutrition coach who's stoked about lifting, the outdoors, summit snacks, and my dog.


I understand that fitness is not your whole life. Fitness is a PART of your life. I approach training in a way that adds value to your life and longevity, so you can enjoy being active whether you're romping around in the mountains, playing with your kids, or signing up for your first 10K race.

I'm here to meet you where you are, so you can train safely and effectively, and gain strength and confidence both in the gym and on the trails.

IMG_3783 2.HEIC

Want to be adventure ready year-round?

How about some free knowledge gains?

Sign up for Let's Taco 'Bout It Tuesday, my weekly newsletter. Tacos not included.

Welcome to the fam!

bottom of page