How Do Personal Fitness Trackers Work, and Are They Any Good?

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Photo Credit: Aaron Muszalski, 2013 – Fitness Tracker:

Fitbit, Garmin, Apple Watch, Misfit, Jawbone, Smartwatch? About 20% of us are using personal fitness trackers – so what’s the skinny on these mini devices?

Sigrid de Castella - 'Half the Woman I Was' Author, Speaker and Health & Buisness Coach

Ever wondered how fitness trackers work, and are they all as good as they’re touted to be?  Sigrid de Castella decided to test out some of the most popular brands. Her findings may surprise you.

What is a Personal Fitness Tracker?

A personal fitness tracker, sometimes also called a smart band, is generally a wrist-worn electronic device that has a watch as well as various tracking sensors to measure exercise metrics such as your steps, flights of stairs, exercise sessions, calories burned, heart rate and even your sleep patterns.

How Do Personal Fitness Trackers Work?

In simple terms, wrist-worn devices all measure motion with the use of a 3-axis accelerometer (measuring movement in each direction) and sometimes a gyroscope that measures rotation. This data is then fed into custom-written software (depending on the brand of the device) that analyses and converts, to the best of its ability, the data into more meaningful statistics like steps, distance, calories and stairs climbed.

Devices that monitor heart rate also include an optical sensor (aka ‘the green light’) that shines to illuminate the capillaries under your skin, measuring the rate at which your blood pumps through.

Similarly, sleep patterns measurement uses an actimetry sensor, which essentially measures wrist movement, sometimes combined with other sensor inputs, and analyses it to decide your wake, sleep and restless periods.

Some trackers (especially those designed for long-distance sports like running) also have a GPS to track your real position on the planet via satellites (much like sat Nav for your car). Others include galvanic skin response sensors to measure sweat, thermometers to measure temperature and ambient or UV light sensors or bioimpedance sensors to gain input data for analysis.

To learn more about an individual brand, explore the following Wearable and Digital Trends articles to discover how various fitness trackers operate.

The skinny? Various sensors in the fitness tracker provide raw user data, which is then interpreted by software (using basic assumptions and calculations) into more meaningful data.

Are Personal Fitness Trackers Accurate?

Yes, and no. Personal trackers use varying technology to gain and analyse user data. Still, all rely on user inputs, including weight, stride length, wrist dominance and sometimes height and age, to give more precise reporting. So if you don’t change the default factory settings, your readings will be incorrect.

One University of Pennsylvania study found the step count on fitness trackers could be as much as 22% out when compared with old-style pedometers and accelerometers. But the University of North Carolina’s Professor Kelly Evenson says lab and field tests revealed trackers were reasonably accurate but tended to overestimate distance with slow speeds and underestimate when moving fast.

Fitness Trackers Put To The Test

In a test of 10 fitness trackers, CBNC’s Eric Chemi reported that all devices were close to reporting accurately, but each device did vary slightly. Fitbit Charge HR (which also records sleep patterns) was the most accurate when it came to step counts; Apple Watch for heart rate; and Withings Pulse O2 for distance. But most of these devices record other activities that were not subject to testing.

What is most useful about any fitness tracker is the daily comparison of results by the same user. Just like any gym routine or fitness program, you’re only competing with yourself, and your results are the only ones that matter (despite many trackers having the ability to join virtual groups and compete in weekly competitions). Personal fitness trackers are a way to set targets and track your gradual improvement, or lack thereof.

And most reports, like The Guardian’s Amy Fleming and Shape’s Paige Fowler, tend to agree: it’s about the user being able to check their own data, even if it’s just feedback or a guide to make incremental improvements.

The skinny? All fitness trackers vary slightly in results. However, all fitness experts, including people such as Kevin Morgan, use fitness trackers. 

What are the Best Personal Fitness Trackers?

Right now, the best fitness tracker, according to TechRadar, is the Fitbit Charge 2, which connects with the GPS on your phone, perfect for joggers and runners. Second is Samsung’s Gear Fit 2, third is Microsoft’s Band 2 and fourth is the Fitbit Flex 2. However, the TechRadar report excluded Smart Watches, which are reported separately here.

Wearable, however, rates Garmin’s Vivosmart HR+ the best tracker, with Fitbit Charge 2 coming in second as the best general fitness tracker. They also rated the best trackers for a range of categories, including simplicity, style, parents, getting in shape, tight budget, losing weight, multi-sports and screen quality. Check out their full report here.

PC Magazine’s assessment puts the Fitbit Surge at the top of their list, with the Fitbit Charge 2 and Garmin Forerunner 735XT runners-up.

The skinny? It really depends on what exercises you regularly do and what you want to track.

Which Personal Fitness Tracker is Right?

Men’s Journal quizzed fitness tracker researcher, the University of Pennsylvania’s Dr Mitesh Patel, who likened fitness trackers to a gym membership – the novelty often soon wears off. What was most important, says Dr Patel, is that wearers already had a high motivation towards improving their own health and fitness. It would seem that motivation and personal responsibility for one’s own health are huge prerequisites when it comes to fitness trackers, but these aren’t the only factors.

The ABC’s Joel Werner and Tegan Osborne report that around 50% of people stop wearing their fitness tracker within 12 months of purchasing it. So it seems that the selection of the correct device for the right purpose is crucial to any device’s longevity of use.

What Did Sigrid’s Fitness-Tracking Friends Think?

When I asked my fitness-tracking friends what they liked about theirs, the responses varied. Some liked the technological features like the Fitbit Alta which vibrates with incoming calls, receives SMS and calendar reminders on the watch face; some wanted a tracker that looks more like a conventional watch rather than a band; others talked about the importance durability like the Garmin Vivoactive being waterproof, even in sea water (which might have been helpful for me when I fell into a French canal last year).

Sigrid’s Thoughts

For me, it’s the sleep tracking function of the Fitbit Charge HR that won me over. Being able to see how many times I ‘wake’ and how many times I’m ‘restless’ and my combined sleep total for the night gives me a lot of information to proactively improve my quality of sleep.

A common theme that emerged was the importance of considering the comfort and appearance of the unit (since you wear them 24 hours a day), as well as factors like battery life/recharge time, ease of use, and the user interface (accessible via smartphone or laptop apps).

Other friends use a non-band fitness tracker like Google Fit, which uses advanced sensors in your smartphone to work out when you’re walking, jogging or cycling – good if you are a regular ‘wearer’ of your phone (probably better suited for men. Why don’t they put pockets in women’s clothing?).

Fact: There is a wide variety of devices available at a vast range of prices, from cost-effective to extremely expensive. Finding the correct device is a personal choice, and it may take you a few tries to find the device that’s right for you. Do your research and talk with your friends who use fitness trackers. Find out what they like and dislike about their units, and see if you can try theirs on. And if in doubt, handy services like USA-based Lumoid provide devices for rental so you can ‘try before you buy’.

The skinny? Decide on what’s essential for you, set a budget and do your research before you buy.

How to Use a Personal Fitness Tracker Well

#1 Customise Your Tracker

Once you’ve chosen your personal fitness tracker, the first thing you’ll want to do is customise it. Add in your personal user settings (height, weight, stride, etc.) according to the app to ensure more accurate results.

#2 Set Your Goals

Next, and most importantly, is to decide on what you want to track and set some goals, like hours of activity, heart rate and daily steps. If in doubt, use your tracker for a week first to know what your baseline is, then set realistic goals that stretch you a little more each week.

#3 Maintain Your Motivation

To keep your motivation, you might want to join a virtual group. Many brands have virtual groups in the apps that allow you to connect with others and share selected statistics (like step count). If a friend has the same device brand, you might be able to create a group together, which can be more fun and definitely more motivating. But remember, it’s your week-on-week results that count – you are your only competition.

#4 Log Your Food & Water

If you’re on a weight loss mission, many apps allow you to log your food and water. This can be time-consuming but also a very sobering experience when you realise how little water and how many calories you’re actually consuming. Still, it can be a very beneficial and educational exercise.

#5 Keep Your Mind Open

And when it comes to burning off those extra calories, don’t believe everything you read (or track). Fitness trackers aren’t 100% accurate. In fact, a study from Iowa State University found that there’s more than a 15% margin of error in most trackers. Take the results as a guide and don’t get too overzealous.

#6 Set Movement Reminders

If you tend to sit or be inactive for long periods, set a regular reminder to move. Reminders and alarms are a great way to make sure you’re moving more, but they can also reduce your battery life, requiring more regular recharges.

#7 Consistency & Routine Are Essential

Consistency and routine are the keys when it comes to tracking. Make sure you wear your device for the same hours. Better, or better still, keep it on 24 hours a day – especially for devices that track your sleep patterns. Recharge your device when you’re not moving much, such as when you’re sitting at your desk or in the shower. Most devices fully charge in around 20 minutes and last for 3 to 5 days.

The skinny? Personal fitness trackers can be a great way to monitor your health and well-being. But they require commitment, consistency and routine.

Sigrid de Castella is an internationally published author, speaker, and coach in the fields of health and business. Her book “Half The Woman I Was – How I lost 70kg naturally, reclaimed my life … and how you can too!” has received international acclaim and has been hailed as the most comprehensive weight loss book on the market. Sigrid has also studied Personal Training with the Fitness Institute Australia and has a keen interest in whole food nutrition, natural therapies and all aspects of physical and mental health. Sigrid and holds 

Want to Know More About Sigrid’s Book “Half the Woman I Was”? Then Don’t Hesitate to Watch this Video.

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Disclaimer: The information published in this column is based on each of the author’s own professional and personal knowledge and opinion. This information and opinion are not intended to be a substitute for professional medical advice, diagnosis or treatment of any kind. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding any medical condition, and consult a competent medical professional before beginning any nutritional or exercise program. Never disregard professional medical advice or delay in seeking it because of something you have read on InShape News.