Wearables, Tracker und Fitnessarmbänder,

Wearables, trackers and fitness bracelets, what can they really do?

Richard Staudner
Richard Staudner

The Optimizer

Our smartphone constantly provides us with the latest information about our health.
status, whether we have moved enough and how our sleep was. The data comes
from the smartwatch, a fitness bracelet or a ring on your finger. Immediately we fit
our lifestyle and try to optimize everyday life.
That is pure biohacking! And for this it needs neither large financial resources nor a
Degree in medicine or sports science.

Are we turning into little cyborgs? Well, that's perhaps a bit of an exaggeration.
But in fact, we already have a bunch of technical helpers that can help us with our
everyday life easier and help us to take care of our health.
Trend researchers see this as an important step toward telemedicine. So,
health care at a distance.

Besides the health aspect, the trackers are an important source of motivation.
Graphs, statistics and bar charts on the smartphone are for many people
essential. This makes it easier for them to achieve their personal goals. At least in theory.
If the app thinks we're not active enough, it immediately adjusts calories and
we have to starve a little.

But how accurate are these devices? Do they deliver what they promise and are they also
Manufacturers often state that the accuracy has been tested in studies. How these
studies were built and what the exact results from them are, we unfortunately learn
not very often.
In Quebec (Canada), a research team has addressed this dilemma and has
Independently tested 3 new fitness wristbands: Apple Watch 6, Polar Vantage V and Fitbit

For this purpose, 60 men and women have both strapped on the bracelets, and
also receive scientifically validated heart rate monitors and a breathing mask. The breathing mask
measures the inhaled oxygen and the exhaled CO 2 and can calculate from this quite
exactly calculate the energy consumed. Then the participants performed various
Exercises for 10 minutes from: Sitting on the chair, walking, running, strength training and driving on the


First, let's take a look at the results of the pulse measurement. On the wrist can
only the pulse is measured, not the heart rate, which is the direct measure of the heart rate.
Beating of the heart muscles. For example, if the heartbeat is very weak, it could be
no measurable/perceptible pulse can occur. In healthy people, pulse and

Heart rate very similar! The Apple Watch had the lowest average heart rate here.
Deviations from the actual value, depending on the measured activity it gave way to only 0.6-2.9%
from. Polar Vantage, on the other hand, was 1.8-5.7% deviation and Fitbit Sense was 3.8-5.3%.
Apple creates highly accurate measurements for all activities, Polar while sitting, running and
Strength training, Fitbit only when cycling and running. Especially when running have all
Wristbands a high accuracy, cycling worked the worst. Despite
all: All devices are at least "Good" in heart rate measurement.

What about the calorie consumption? For many the most exciting question!
The authors of the paper explain that the trackers are not able to
Calorie consumption to measure. Instead, it calculates an estimate from the
heart rate and some information that you enter yourself beforehand. The formula is then per
varies by manufacturer, but the perfect formula does not yet exist.
This is also reflected in the results: For all activities and all devices, the
calculated energy consumption differs significantly from the scientifically measured result.
No wristband makes it below an average of 14% deviation. Worst case
the devices even deviated by an average of 47%. Thus, the quality of all models is considered to be
"Poor. The most difficult for the bracelets was the need for sitting and walking
and during strength training. The "smallest" deviations were found during running.
But even here, the devices average 14.9% (Apple Watch), 15.7% (Polar Vantage)
and 17.8% (Fitbit) next to the actual value. Converted to one hour, one is
here quickly times 100-130 kcal off. If you look at the calorie intake after
oriented, you are of course wrong. Not gravely, but it can be seen over a
training week do add up.

Step by Step

A Systematic Review, that is, a summary of many study results, looked at
also look at the pedometers. To lump together many studies here is of course
difficult, a lot has happened in this sector in recent years. The studies
show that quite accurate measurements came out with the steps. Best
Apple and Samsung manage that. Apple, Fitbit, and Garmin were also at almost 50% of the
Studies in the desirable range. This Systematic Review also looked at the topic
energy consumption and found that the sports wristbands for measurements of this type
are not suitable. According to the authors, no brand is considered to be the "gold standard" of the
Fitness wristbands on display.

What does it mean?

They can measure heart rate. So to assess performance and choose the right
The three examined sports wristbands are well suited for the training intensity.
The sports wristbands are also very suitable for counting steps. Some more than
others, but for the motivation boost to get to 10,000 steps, it's enough on
any case.

Energy consumption calculation, on the other hand, is not an easy task for the trackers tested. Also the
Author:inside would have expected a better result. Because this would be for other
scientific investigations a great advantage and a strong simplification. But
also has significance for our everyday lives and health awareness: we use the
devices to get accurate results. An estimate of our consumption

we could set up without expensive trackers. But when we track our calorie intake
exactly to our consumption, then we really have to be careful here! The
Of course, fishing in the dark is undesirable for people who want to lose weight and athletes. Accurate
Numbers are very important for optimal nutrition. Neither a permanent surplus is
meaningful, still a deficit, especially when it comes to performance improvement.
With regard to the energy demand, it does not hurt to rely once more on our intuition.
instead of fixating on the numbers on the smartwatch.
An objective look in the mirror and regular reflection can make the bracelets
not yet replace.


Systematic Review: Fuller, D., Colwell, E., Low, J., Orychock, K., Tobin, M.A., Simango, B.,
Buote, R., Van Heerden, D., Luan, H., Cullen, K., Slade, L., Taylor, N.G.A., 2020. reliability.
and Validity of Commercially Available Wearable Devices for Measuring Steps, Energy
Expenditure, and Heart Rate: Systematic Review. JMIR Mhealth Uhealth 8, e18694.

Apple, Polar and Fitbit study: Hajj-Boutros, G., Landry-Duval, M.-A., Comtois, A.S.,
Gouspillou, G., Karelis, A.D., 2022. wrist-worn devices for the measurement of heart rate.
and energy expenditure: A validation study for the Apple Watch 6, Polar Vantage V and Fitbit
Sense. European Journal of Sport Science 1-13.


Richard Staudner

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