Does your wearable device track your health accurately?

Wearable health trackers have become the go-to gadgets for fitness enthusiasts and health conscious people. These modern marvels claim to measure everything from your steps and distance to your heart rate, calories burned, quality of sleep and even stress levels.

But it’s time to answer an important question: are these devices as accurate as they claim, or are they just trendy tech accessories? Let’s find out the truth about your favorite fitness trackers.

Factors Affecting Wearable Tracking Accuracy

There are several pros and cons to buying a fitness tracker. One consideration should be how accurately these devices do what they claim to do.

Proprietary tracking algorithms and methods

One of the biggest factors affecting the accuracy of health trackers is the algorithms and proprietary tracking methods used by various companies. Each brand, whether it’s Apple with its focus on wellness, Samsung with its BioActive sensor, Fitbit with its various models, or any other, has its own algorithms that process raw sensor data to provide you with your health metrics. .

These algorithms are often kept secret, which makes it difficult to assess their accuracy and compare them to each other.

Differences in individual physiology

Another factor to consider is the variation in individual physiology. People have different body types, fitness levels, and health conditions, which can influence how their bodies respond to exercise and other activities.

Since most wearable devices are designed based on general population data, they don’t always account for these individual differences. This can cause deviations in health parameters, especially for people who are outside the “average” range.

Positioning and Wear of the Smartwatch

How you wear your smartwatch can also impact its tracking accuracy. Most smartwatch manufacturers recommend wearing the device snugly on your wrist, just above the wrist bone. However, factors such as wrist size, shape, and even how you move your arm can affect measurements.

If the smartwatch is too loose, it may not maintain constant contact with your skin, leading to inaccurate heart rate readings. For example, if you’re like me and use your smartwatch while mountain biking, you can wear your smartwatch upside down for more comfort. You will still be able to navigate, but you will lose all heart rate readings.

Limits of sensor technology

Finally, limitations in sensor technology play an important role in tracking accuracy. Although wearable device sensors have come a long way, they still have their shortcomings.

Some devices may use more advanced sensors, like the BioActive sensor found in Samsung Galaxy watches that can measure the amount of muscle, fat, and water in your body. Others might use less sophisticated technology, as is the case with some budget fitness trackers (like the $50 Amazefit).

The type and quality of sensors can greatly affect the accuracy of the data collected.

Accuracy survey of popular smartwatches

Each fitness tracker brand offers a unique set of unique capabilities, but how do they compare in tracking accuracy?

To get a clearer picture of how these smartwatches perform, we can compare them to benchmark measurement tools such as pedometers for counting steps, chest strap heart rate monitors, metabolic lab tests for estimating calories burned and sleep study equipment for sleep tracking.

Accuracy of pedometers

When it comes to counting steps, pedometers are the classic choice. They measure steps using a simple mechanical or electronic mechanism that detects movement as you walk or run. In contrast, smartwatches rely on algorithms that process data from accelerometers and gyroscopes to count steps.

Although smartwatches generally provide reasonably accurate step counts, they can be influenced by factors such as walking speed, arm movement, and other activities that can lead to false step readings.

A study published in the Journal of the American Medical Association measured the accuracy of pedometers in wearable devices and smartphone apps. The results show that these devices can be reliable at accurately tracking the number of steps you take.

Accuracy of heart rate monitoring

When it comes to measuring heart rate, chest strap heart rate monitors are among the most accurate because they use electrical signals from your heart to measure beats per minute. Smartwatches, on the other hand, use optical heart rate sensors that measure changes in blood flow through your skin.

Although smartwatches provide reasonably accurate heart rate readings during steady-state exercise, they may struggle with accuracy during high-intensity or irregular activities due to factors such as arm movement and sweat.

Research published by the Journal of Personalized Medicine measured the accuracy of wrist-worn devices, including devices from Apple, Fitbit and Samsung. Research has concluded that most wrist-worn devices are accurate for measuring heart rate in laboratory activities.

But do lab activities simulate the real world well enough? Researchers at Harvard University report that accuracy depends on activity. For example, while walking, smartwatches and wrist devices tended to report a higher heart rate than the actual heart rate. While typing, wearables reported heart rate lower than actual heart rate.

Other research published by the Journal of the American Medical Association Cardiology reports that chest strap heart rate monitors had a 99% correlation with an electrocardiograph, making them the go-to option for those who want precision monitoring. .

Accuracy of calories burned

Metabolic lab tests, the gold standard for estimating calories burned, measure oxygen consumption and carbon dioxide production to calculate calories burned.

By contrast, smartwatches and fitness trackers like Fitbit estimate calories burned using algorithms that take into account variables such as heart rate, age, weight, and activity level. The accuracy of these estimates can vary depending on the individual and the specific activity, making them less accurate than lab tests.

A study published by the European Journal of Sports Science measured devices from three manufacturers, including Apple, Polar and Fitbit. He concluded that in terms of measuring energy expenditure (i.e. calories burned), all three devices had poor accuracy during all activities. That’s not to say that smartwatches won’t one day be able to accurately track this metric, but they currently don’t accurately track calories burned.

Sleep Tracking Accuracy

Clinical sleep study equipment, such as polysomnography, measures brain activity, eye movements, muscle activity, and heart rate to accurately track sleep. This level of accuracy is currently only available in clinics and you will need to sleep in a clinic to get this level of measurement.

On the other hand, wrist-worn devices are limited in the data they can collect from a single point on your body. For this reason, they rely on accelerometers and heart rate data to estimate sleep stages, which can be less accurate.

According to Johns Hopkins Medicine, wearables can be useful in helping you recognize sleep patterns, and they can provide something to think about, but none of the wearables on the market can actually measure sleep directly and should be taken with a grain of salt. For measuring sleep directly, there is no substitute for clinical-grade equipment.

Benefits of Accurate Fitness Trackers

Smartwatches and fitness trackers have revolutionized the way you can monitor your health and fitness, offering valuable insights into various aspects of your well-being. These devices have made significant advances in accuracy. A 2022 meta-analysis by the Journal of Medical Internet Research confirmed that wearables can be effective at measuring steps and heart rate (especially when using a chest strap for the latter), but not the calories burned. The accuracy of sleep tracking also remains questionable.

A review of recent research published in The Lancet Digital Health indicates that the benefits of wearing a fitness tracker outweigh the potential downsides. For example, these devices appear to be effective in increasing physical activity in general.

Trust your activity tracker

Fitness trackers get more accurate with each iteration. And while early versions may have been grossly inaccurate, newer devices can be incredibly useful in motivating you to stay active, set goals, and track your progress over time. That’s reason enough to try this type of device if you want to give your wellness journey a boost.