In today’s health-conscious world, fitness trackers are everywhere – becoming almost as common as smartphones.
From the gym to the office, wearable devices like the Apple Watch, Oura Ring and Fitbit can be a great tool for staying motivated, setting goals, and feeling more in control of your health.
These small devices promise big results—tracking your steps, monitoring your heart rate, logging your sleep, and giving you insights that can support your fitness, nutrition, and lifestyle goals.
But regardless of which device you use—or if you’re considering investing in one—you’ve probably wondered: Are these things actually accurate?
As the consumer, what do you need to know about the information these devices provide that you are so reliant on?
And how do you make these tools work for you—rather than letting them run the show?
In this blog, you’ll learn:
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What fitness trackers measure
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Which metrics you can trust (and which to take with a grain of salt
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How to best use your tracker to build healthier habits and maximzie results!
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WHAT DO FITNESS DEVICES MEASURE?
Fitness devices monitor a wide range of metrics that you can use to assess and understand how your own personal habits that impact your overall health and fitness.
Most devices nowadays measure and provide you with data on the following metrics:
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Heart Rate: Scans your pulse all day and during exercise.
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Step Count: Estimates your daily steps using accelerometers and gyroscopes
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Sleep Patterns: Tracks your sleep stages using motion sensors and heart rate variability
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Sleep Cycles: Tracks sleep cycle 0your general bedtime, when you hit REM (deep) sleep and your resting heart rate.
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Activity Type: Categorizes movement into activities such as walking, running, cycling, or high-intensity workouts.
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Calories Burned: Estimates calories burned throughout your day and / or workout.
Not all fitness devices are created equal, as each brand has its strength. When using or purhcasing, you want consider how you will be using the data and which metric(s) are most important to you:
- Apple Watch – offers seamless integration with iPhones and various health-tracking apps, making it great for both casual and serious users.
- Fitbit – provides user-friendly tracking with a focus on health insights and goal setting.
- Oura Ring – worn on the finger, more subtle in design and shines when it comes to sleep and recovery metrics.
If you’re looking to build healthier habits, all of these can help—but it’s important to understand what you’re actually looking at.
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WHAT FITNESS TRACKERS GET RIGHT!
You can feel confident relying on your device for a few key metrics like heart rate and step count, as most top-tier devices (Apple Watch, Fitbit, and Oura Ring) perform around 90–95% accuracy.
Heart Rate: Most devices are 90–95% accurate when tracking heart rate during rest or low-intensity activity such as walking or jogging, and high-intensity activity such as running a 10k or strength training
Step Count: Fitness trackers do a good job of step counting for average walking, though they can be less accurate for non-walking movements like pushing a stroller or carrying groceries.
When loooking to improve your health, fitness trackers can be a powerful tool for building awareness and creating healthier habits. Having this kind of real-time feedback helps you spot patterns, stay consistent, and make smarter decisions around your habits and health.
For example, if you’re always restless at night, check your step count. Maybe you didn’t move much that day, and your body wasn’t tired enough to wind down.
Or, if you’re always dragging on Monday mornings, your device might show a trend of late bedtimes on Sunday nights.
Some devices remind you to stand up and move around if you’ve been inactive for too long—like a little nudge to break up your sitting streak at work.
Think of your body like a battery that’s meant to be used during the day and recharged at night. The more you move, the more energy you burn—and the more your body needs deep, restorative sleep to recover!
On days when you don’t move much, your body may not feel tired enough to fall asleep easily. Less movement = less need to recharge = lower quality sleep.
Bottom line?
Fitness trackers can help you make small, meaningful changes and build better habits that can improve your health and mxaimzie your results—especially when you start connecting the dots between how you move, sleep, and feel.
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WHAT FITNESS TRACKERS GET WRONG
While it’s tempting to obsess over the “calories burned” number after a workout, this is where your fitness device can do you wrong. Estimates can be way off—by as much as 60% depending on the brand – when calculating calories burned.
Your Apple Watch might estimate you burned 800 calories from a workout while another device like Fitbit estimates 300 for the exact same session.
That’s a very BIG discrepancy, especially if you use total calories burned data to track calories in and out for weight or fat loss goals.
over time, this could delay, stall and totally hinder the results you want – here’s how:
Your fitness tracker says you burn 2,153 calories per day so you plan to eat 1,750 calories a day so that you are in a calorie deficit to lose weight.
However, after months of tracking calories, you haven’t lost any weight- you’ve acutally gained some – what’s up with that!?
A hidden issue might be an inflated number. If there is a 40% discrepancy in your calories burned, then you may be over consuming around 450 calories each day.
Why is there such a huge discrepency among devices? Let’s take a closer look at why total calories burned varies among devices and is not very accurate:
- Different algorithms: Each company uses its own proprietary algorithm based on your biometric data and heart rate to estimate calorie burn.
- Activity classification errors: If a device misidentifies your activity (for example, calling weightlifting “walking”), it might apply the wrong metabolic equivalent to calculate your burn.
- Body variability: Everyone’s metabolism is different. Calorie burn can be affected by muscle mass, fitness level, stress, sleep, hormones, and more—most of which trackers do NOT fully account for.
Your tracker isn’t measuring calories—it’s estimating them based on limited data. So…does this mean you should disregard and ignore calories burned? Not exactly.
You can still use this number—but don’t trust it as exact.
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GET THE MOST OUT OF YOUR DEVICE:
Now that you understand more about your device’s data and accuracy, Here’s how to use your device like a pro:
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Focus on Consistency: Daily step goals, regular workouts, and better sleep routines pay off—regardless of the exact numbers.
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Track Trends, Not Absolutess. Are you getting more steps or sleeping longer? Look for patterns over time, not just what one day tells you
- Pick the right tool for your goals: Oura Ring for recovery and sleep, Apple Watch for workout performance and syncing with other health apps, and Fitbit for general lifestyle tracking.
- Track Calories More Accurately: If your goal is fat loss, muscle gain, or just better nutrition habits, apps like MyFitnessPal or Cronometer are a much more accurate way to track what you eat and how much. These apps make it easy to align your caloric intake with your body’s needs and your goals!
For extra clarity and support, working with Amie, our certified nutrition coach, takes out the guesswork! Working with a coach helps you understand exactly how much you need to eat for your goals—and give you the tools to track progress with confidence!
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Fitness trackers have revolutionized how you engage with your health and fitness, providing motivation, accountability, and insights that were once only available through expensive lab tests or guess work.
Ultimately, fitness devices are most powerful when used as part of a broader awareness of your body, your goals, and your lifestyle, not as the ultimate judge of your health!
They help build awareness, spark motivation, and track helpful trends over time. Use them to stay consistent, notice patterns, and take charge of your habits but don’t let the numbers run your life—especially when it comes to calories burned.
They’re best used alongside real-world tools like food journaling, strength training, and working with a professional coach who understands your personal goals and your body.
When used wisely, these devices can support a healthier, more informed, and more empowered you!