Apple, Fitbit, and other fitness trackers have biases you need to know

The promise of fitness trackers, of course, is to quantize and optimize fitness. Some activity is always better than no activity, but for the best results you need to figure out how many calories and nutrients you are consuming and how to work harder, better, and faster. Before picking up a Fitbit, Samsung, or Polar device, it’s important to know that all major trackers are geared toward cardio exercise.

It should be noted that “bias” in this case does not mean that companies are unfair or even necessarily willful. Rather, trackers (and their Android and iPhone apps) are primarily optimized for cardio. Modes for activities like yoga and weight training are commonplace – but the value of fitness trackers is diminished to them.

For our purposes, we continue to define cardio as workouts such as running, walking, or cycling and, to a lesser extent, ellipticals, rowing machines, or battle ropes. While most workouts get your heart racing, cardio makes this a primary goal.

With a few chest straps and other exceptions, most trackers come with gyroscopes. Comparing live data with expected patterns makes it possible to track repetitive movements such as running and walking. A Fitbit, for example, calculates a wearer’s “steps” based on their rocking motion.

Step numbers can be a helpful metric for the average person. However, they are easy to fake, and even if someone is completely honest, trackers will often count incorrectly. In fact, companies are already starting to use other metrics like active minutes. Serious runners don’t pay attention to their steps at all – they’re more concerned about pace, efficiency, heart rate, and oxygen levels.

If gyroscopes are unreliable for something as simple as walking, they are even less suitable for complex activities like dancing or those with little wrist movement like pull-ups. Even barbell squats and bench presses are difficult to follow consistently because lifters use different grips and ranges. Some companies make an effort in this regard – Garmin, for example, allows people to track sets and repetitions – but this data usually needs to be corrected later, which is devoid of any convenience. It is often easier to write things down on paper.

The only type of sensor with a universal value is the heart rate. Combined with details like age and weight, a properly worn optical or EKG sensor can give a sense of how well you’re doing and be a standard figure for calorie expenditure. In fact, many people do something called zone training, in which they try to keep their heart in a target area. Fitbit, Garmin and Polar watches in particular take the zone concept into account.

However, many activities are unsuitable for zone training, and wrist heart rate sensors are the least accurate when the intensity dips and increases – for example, when starting a 300 pound deadlift after a 60-second break. It’s worth noting that some high-end RF sensors on the wrist can compete with more accurate chest straps, but this is a rare case.

Heart rate cannot fully measure performance in many cases either. Weightlifters are most concerned about strength and overall weight, while activities like yoga and Pilates are as much about mobility and endurance as anything else.

See also: The best heart rate monitors and watches

It cannot be emphasized enough that even the best heart rate sensors – like the EKG units on chest belts, generally the most accurate consumer option – can only give a rough estimate. Many factors determine calorie consumption in the real world, so trackers can often cut hundreds of calories, which can make the difference in whether someone is trying to gain weight or lose. An estimate can be useful, but only as a starting point for personal tweaking, and this is especially true for people who work outside of the cardio field.

Topic # 3: The Fickle Nature of Public Demand

All device manufacturers thrive or die based on consumer demand. In view of finite resources, it makes sense to target products to the largest population group. The result of fitness trackers is that they are being marketed to cardio aficionados – there are more people running, walking, and cycling than there are pumping iron. This, in turn, is because people are more likely to worry about weight loss or general heart health than things like strength or flexibility.

The effect is not only evident in the hardware specifications, but also in apps like Apple Fitness and Google Fit, which prioritize cardio activities. The former encourages people to close their daily move rings, while Fit rewards users with “heart points”. Some apps go a step further and assume that your goal must be weight loss – Polar Flow, for example, will regularly chastise you if you gain weight. It doesn’t matter if those extra 10 pounds are mostly muscle.

Is someone trying to get around the cardio bias?

Beyond Garmin, perhaps the best efforts to handle the situation come from Coros. With the fitness watches of the last-mentioned outfit, structured strength training can be set up via a mobile app, in which even individual muscle groups can be specifically addressed through a series of selectable exercises. This addresses a more important concern than rep counting – making sure the workout hits each muscle often enough to trigger growth. Coros devices start at $ 200 for the Pace 2, although the cheapest model with a touchscreen (none required) is the $ 500 Apex Pro.

Read: The best running watches you can buy from Garmin, Polar, Coros, and more

There have been some extreme niche efforts, such as the $ 495 flex dumbbell sensor. One of the earliest wrist strength trackers came from Austin’s Atlas Wearables, but its products never made it mainstream as a solo company. That could change – Atlas was bought by Peloton in March 2021 and Bloomberg reports that the company is developing a wristband that can be paired with Peloton’s bikes and treadmills. While the focus should obviously be on cardio, Peloton incorporates some strength training and could use Atlas’s algorithms.

Recommended trackers for non-cardio workouts

Coros’ Pace 2 and Apex Pro are a logical choice for people who focus on strength and insist on taking the watch route. If you don’t need a new watch and / or aren’t interested in strength, it may be easier (for fitness beginners) to choose a chest strap or armband. The gold standard for chest straps is the Polar H10, a model that supports both Bluetooth and ANT + connections and can cache the data of a single session so you don’t have to have your phone nearby. Since it’s a couple of years old, it can be regularly found under its $ 90 price tag.

Optical wristbands are less accurate than chest straps, but are usually more comfortable and can be a good tool for people who want to keep their wrists free. Polar is once again leading the way thanks to the $ 90 Verity Sense, which can store up to 600 hours of data and even clip on to goggles to track your heart rate from your temple. A solid alternative is Scosche’s $ 90 Rhythm + 2.0, which has no memory but has a 24-hour battery.

As long as there is a decent HR sensor, most people can realistically get by with a standard tracker or smartwatch on their wrist – especially if fitness functions aren’t a priority. It’s just a matter of acknowledging and adapting to prejudice what any fitness product currently requires. It may take a few more years before hardware and software can close the gap.

Next: The best smartwatches you can buy