Many users of fitness bracelets and smart watches are confident that the pulse counting used in smartwatches is the key to accurate data on calories burned.
However, doctors interviewed by Tech Facts are more critical of these indicators. In their opinion, calories on the screen of a smartwatch are often entirely incorrect forecasts.
How wrong can gadgets be in counting calories and what is the best way to count them – in the tech facts article.
Pulse is not the key to accurate data.
Counting the pulse in a smartwatch or by other methods is not an accurate key to data on burned calories. Olga Demicheva, an endocrinologist and palliative care specialist, told tech facts.
“Even if you measure your pulse around the clock and very accurately, you won’t be able to calculate the number of calories burned based on this parameter alone. Modern fitness bracelets measure your pulse quite accurately. During jogging, the error in the pulse monitor on bracelets and smartwatches, according to manufacturers, does not exceed 5%,” she explained.
It is important to remember that the accuracy of the same heart rate monitor may differ for some users, and there are several reasons for this.
According to Demicheva, sometimes people wear fitness trackers not on the outer surface of the wrist, like a traditional watch, but on the inside. Intuitively, it seems like a good idea because you can see the veins and feel the pulse there. But the pulse detection technology of “smart” watches is designed specifically for wearing them on the outside of the wrist, the endocrinologist added.
“And, once again, counting the pulse does not provide accurate data on how many calories a particular person burns, even if the error in the calculation is minimal,” the specialist emphasized.
“The main problem is that this method does not consider all the factors that affect a person’s physical activity. For example, when doing strength training or training with heavy weights, where the load on the body is high, smart watches often underestimate or overestimate the calories burned,” he noted.
Calories on the screen are just a forecast
Any fitness bracelet or smart watch calculates the indicators by considering the user’s entered physical data (gender, weight, height, and age). The doctor said this information automatically calculates the basal (at rest) and active (under load) metabolism.
“No wearable device can yet determine the presence of an inclination angle or the type of surface on which a person is running or walking. The gadget for determining physical activity takes into account the heart rate monitor readings and also takes into account the entered data about the user,” the endocrinologist added.
According to her, each company uses its algorithms to calculate calories burned. Almost always, the algorithms are based on the principle of comparing your numbers with a pre-loaded data set of people of different weights/genders/ages and the amount of energy they expend during different activities.
“This average information does not allow for an accurate interpretation of an individual user’s data. In addition, “smart” watches can make mistakes, incorrectly interpret random hand movements, or suddenly increase heart rate due to stress. All this will introduce an error in the overall accounting of calories burned,” she is sure.
According to various studies, fitness tracker calorie counting errors can reach 25% or more, Demicheva noted. She noted that more errors occur during walking than during running or cycling.
“Smart” watches perform certain calculations, but these are “speculative calculations, no specifics,” a nutritionist and leading researcher at the Federal Research Center for Nutrition and Biotechnology told tech facts.
“I think these are marketing ploys to popularize these gadgets. Like any health program that counts how many calories you’ve burned step by step. Or how many calories you’ve burned on a treadmill. These are approximate things. It’s better to resort to some medical data, to use it,” she said.
the doctor said the indicators on the screen of the “smart” watch are only approximate forecasts. The specialist noted that the accuracy of such devices, especially during power loads, can fluctuate significantly.
“Deviations can reach 25%, especially during weight training or non-cardio activities. This is because smartwatches cannot correctly consider the load’s variety of movements and intensity,” the doctor assured.
How Calories Are Really Counted
Doctors have a more precise and complex way of calculating calorie expenditure, that is, changes in metabolic processes in the body.
“We calculate these indicators during a breath test based on the nitrogen released in the air and the urine. Usually, a background study is done first, the so-called basal metabolic rate, and then after eating, your energy metabolism can be recalculated after physical exercise. These are special studies that need to be done in a competent institution,” she explained
According to tech facts, indirect calorimetry really remains the most accurate method for calculating calories burned.
This method involves measuring the volumes of oxygen consumed and carbon dioxide exhaled, which allows for an accurate determination of energy expenditure. However, this method is difficult to use in everyday life due to the need for special equipment,” the specialist said.
There are many methods for counting calories, but there is no need to focus on this issue, as this can lead to a neurotic disorder, warned.
“It is enough to step on the scale once a week to control your body weight: it directly depends on the intake and expenditure of energy. Do not try to correct the situation if your body weight is excessive or insufficient. Consult a doctor,” they advised.
Calorie intake matters too
According to specialists, the most important thing in physical exercise is not immediate weight loss because water is lost mainly.
“The main thing is prolonged loads with an increase in muscle mass and loss of fat; this is most important for our health,” the specialist noted.
This can be done using bioimpedancemetry—an analysis of the amount of fat and fluid in the body, muscle and bone mass, and metabolism. There are also such “smart” scales that can show changes in your body once a week. This is a competent calculation, she stated.
Fitness bracelets and smartwatches, despite their flaws, generally encourage people to lead healthier and more active lifestyles.
“Even if a person does not know exactly how many calories have been expended, he can still see whether he needs to walk extra today, and whether 15 minutes of walking will be enough or whether at least an hour is required,” the doctor noted.
advised to consider not only the calories burned since their calculation is only part of the task. The specialist emphasized that to control weight, it is also necessary to consider calorie intake.
“One kilogram of fat contains about 9,000 kcal, and without taking into account the incoming calories, weight control becomes almost impossible. It is important to monitor the balance of consumed and expended energy to achieve the desired result,” he concluded.
