Fitness trackers are a common asset to anyone interested in health and fitness due to the wide variety of things they can track daily. Exercise, blood pressure, calories in and out, body composition, location, heart rate, and sleep are all things that fitness trackers can track.
Out of these, the ability to track calories in and out is possibly the most important feature when it comes to health, as calories control how you gain/maintain/lose body weight. Tracking calories is the easy part. You simply enter the foods you’ve eaten throughout the day on one of the many calorie-counting apps likely linked to your fitness device.
However, tracking calories is a more complex process.
How Do They Do It?
Modern fitness devices use several methods to track how many calories you spend throughout the day. Although they may seem complicated, they’re quite simple.
Heart Rate
Your heart rate can tell a lot about you. When you exercise, it can tell how hard your body is working. When your heart beats faster, it indicates heavier breathing and more energy expenditure. Or in other words, calories burned.
So how does it get this information? By using photoplethysmography (pulse oximetry), your fitness device can detect differences in the color of your blood. It uses a little red/green LED light on the underside of your device. Some of that light reflects and indicates changes in the color of the blood.
These changes represent changes in oxygenation. Every time your heart beats, your blood becomes more oxygenated.
BMR
BMR, or Basal Metabolic Rate, is calculated using information manually entered into your device. Information such as height, weight, age, and gender are typically prompted during the initial setup of your device. Your BMR represents the lowest number of calories your body burns on a daily basis, only carrying out essential bodily functions like digestion and breathing.
Using BMR, a fitness device can calculate how many calories you’ve burned in a day outside of the physical activity. If the device only calculated calories burned from physical exercise, then it wouldn’t be accurate at all.
Movement
How much and how often your body moves significantly affects how many calories you burn every day. Maybe you went up the stairs a few more times, or walked instead of driving; maybe you took your dog on an extra walk. All of these little activities add up and make a big difference when calculating your daily calories.
Gyroscopes and accelerometers are what give fitness devices their ability to track movement. Gyroscopes measure changes in orientation as well as angular velocity, which is how fast an object changes orientations. Accelerometers measure acceleration forwards and backward, body tilt, and elevation.
The more your body moves, the harder it’s working. Thus, the more calories it burns.
Skin Temperature
Most fitness devices will also contain a temperature sensor. This sensor measures changes in your skin temperature throughout the day. When your temperature rises, it signals a more demanding exercise which translates to more calories burned.
Manually Recorded Data
This method only applies when someone forgets to wear their device during a workout or activity. If this happens, all you need to do is manually enter whatever activity you participated in and for how long, and your device will do the rest, just like magic.
Is It Accurate?
When a fitness device uses all these methods together, it can be quite accurate. However, some devices only use some of these, so do your research before you buy to ensure you’re getting the most reliable one.
Using heart rate to measure calories burned isn’t the most accurate method as many different things can affect it besides movement. Simply being anxious or scared can raise it as well.
BMR can also be inaccurate. Since BMR uses equations to estimate your daily fuel expenditure while resting, it leaves room for error. There’s a 60-65% margin of error when it comes to this. So while it could be accurate for someone else with the same measurements, the same BMR for you could be false.
Manually recorded data is one of the least accurate ways to record calories burned. If you aren’t wearing your device when you work out, it can’t calculate skin temperature, heart rate, or acceleration data. Losing all of this data makes the tracking significantly less accurate; however, it can still give a good estimate. It would probably be best to avoid this method altogether.
Benefits of Tracking Burned Calories
There are many benefits when it comes to counting how many calories you’ve burned each day. Calorie tracking is a great option if you want to gain/maintain/lose weight.
Tracking calories in and out is considered one of the most straightforward ways to lose weight. Your body burns a certain amount of calories daily (BMR) to perform necessary functions. If you eat more than that number, your body will gain fat weight. If you eat the same amount of calories, you will maintain your current weight. If you eat less than that amount, you will lose fat weight.
If you exercise at all in a day, then those calories are added to your BMR and the amount needed to consume for weight gain/maintenance/loss is adjusted accordingly. This is why counting your calories out can be such a big game-changer. It allows you to control how much your weight changes or fluctuates and keep track of how many calories you need to consume in a day to reach your goals.
However, counting calories can be quite detrimental for some people. It can lead them to eating disorders or unhealthy eating habits, which isn’t the goal of calorie counting. Many other options besides calorie counting can help you reach your goals.
Conclusion
In short, fitness devices are a good way to keep track of your calories and overall fitness by using multiple calorie counting methods and keeping you aware of your daily exercise habits and how many calories have been burned. We hope this helps you on your fitness journey.