Fitness trackers and cycling: a match made in heaven, or the odd couple?

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Fitness trackers were once touted as the next big thing in consumer electronics, and two companies — Fitbit and Garmin — have set their sights on cyclists with two tiny wrist-based models packed with features such as optical heart rate monitors and GPS. On paper, both sound like they could potentially replace a handlebar-mounted computer while retaining the usefulness of a day-to-day smartwatch. But can they, really? After a few months with the Garmin Vivoactive HR and Fitbit Surge, let’s just say that US technical editor James Huang won’t be making the switch any time soon, but the future is potentially very, very bright.


Why go wearable

“Wearables” are basically just tiny computers packed with sensors and worn somewhere on your body to fulfill various purposes, many of which are geared toward encouraging some level of regular activity throughout the day. These so-called fitness trackers (often also referred to as activity trackers) typically use some type of accelerometer to record how many steps you’ve taken in a day, while others also incorporate optical heart rate sensors to monitor your pulse around the clock. Many will also record how long — and how well — you sleep.

The most popular models, such as the Apple Watch and various offerings from Garmin and Fitbit, are worn on your wrist and sometimes serve double duty as a smartwatch, alerting you to incoming text messages, emails, and phone calls, controlling your playlists, and performing whatever duties for which an app has been created.

In the context of cycling, though, the most interesting wearables are the ones that not only track your general health statistics, but also incorporate GPS to record your ride data. Much in the same way as conventional handlebar mounted computers from Garmin, Wahoo Fitness, Lezyne, Magellan, and others, these GPS-enabled smartwatches use orbiting satellites to pinpoint your location and speed, calculating your ride distance and route along the way.

Can a wearable GPS device replace your handlebar-mounted computer? Maybe - but probably not.
Can a wearable GPS device replace your handlebar-mounted computer? Maybe – but probably not.

On paper, there’s a lot to like with these fully featured, GPS-equipped wearables. The Garmin Vivoactive HR and Fitbit Surge models covered here, for example, are both fairly reasonably priced at US$250 / AU$399 and US$250 / AU$349, respectively. That’s more expensive than a barebones Garmin Edge 25, but substantially cheaper than a Garmin Edge 520, while bundling a wealth of smartwatch features that neither of those options provides.

Garmin Vivoactive HR vs. Fitbit Surge, from a cycling perspective

As someone who regularly visits far-off riding destinations (both with my own bike or using a loaner), I’ve long contemplated the idea of a cycling-friendly GPS device that travels with me, instead of one that needs to be repeatedly transferred from bike to bike. In that sense, the Garmin Vivoactive HR and Fitbit Surge both fulfill that requirement, albeit with a healthy list of caveats.

In cycling mode, the Garmin Vivoactive HR most closely mimics the company’s more traditional Edge 25 bike-mounted computer with basic speed, distance, time, and heart rate functions along with a trio of data screens, each with three lines of data. Having the display on your wrist certainly isn’t as convenient as having it right in front of your bars, though, and the Vivoactive HR’s actual display is quite small at 21x29mm. That said, the full-color screen is impressively bright and crisp with excellent resolution and a handy backlight, and it’s easy to view even in direct sunlight.

The Vivoactive HR establishes its physical location very quickly, too, no doubt aided by its dual GPS-and-GLONASS hardware, which uses both the US and Russian networks of orbiting positional satellites. As a result, it also does a very good job of maintaining a signal lock through mountainous and urban areas.

The performance of the built-in optical heart rate monitor works is decent, but a little disappointing. It’s not as accurate, consistent, or reactive as a traditional chest strap, lagging behind by several seconds and occasionally straying as far as 10-20bpm, seemingly at random. The heart rate data quality is at its best when the watch is worn tightly around your wrist so as to create a more light-tight seal between the sensor and your skin, but that also makes it less comfortable while riding, and it still doesn’t eliminate the accuracy issues entirely.

The Garmin Vivoactive HR's optical heart rate sensor provides more reliable data than the one used on the Fitbit Surge, but not by much.
The Garmin Vivoactive HR’s optical heart rate sensor provides more reliable data than the one used on the Fitbit Surge, but not by much.

Thankfully, the Vivoactive HR can be paired with wireless heart rate chest straps (and speed and cadence sensors should you desire), although you’ll have to make sure those sensors use the ANT+ protocol; Bluetooth is only used to pair the Vivoactive HR with its associated smartphone app. Either way, the Vivoactive HR can’t be paired with any sort of power meter.

As far as cycling is concerned, the Fitbit Surge is far more limiting.

Although roughly the same height as the Vivoactive, the Surge looks and feels bulkier with 5mm of additional width, a thicker casing, and a generally blockier form factor that isn’t as comfortable to wear. That additional surface area provides more room for a bigger screen, though, and the Surge indeed packs a correspondingly larger glass surface measuring 31mm-wide by 30mm-tall, as compared to the the Garmin’s more modest 27 x 31mm cover.

Looks can be deceiving, however, as the display is actually smaller.

When describing the screen size of the Surge, many publications have only referenced the size of the glass cover. But when you account for the Surge’s larger bezel, the functional display area shrinks to a minuscule 21 x 24mm — the same width as the Vivoactive HR, but a substantial 5mm shorter. Moreover, the Surge touchscreen is monochrome and notably low-resolution, and while the smart backlight feature is a neat touch (it automatically turns on when you bring the watch up toward your face), it’s harder to read while on the move.

Moreover, the three-line display’s top two lines are fixed with elapsed time and distance; the lower one can only be toggled between average speed, heart rate, estimated calories burned, and time of day.

Unlike the Vivoactive HR, the Surge can also only connect with GPS satellites, not GLONASS ones, and it’s frustratingly slow to find its position as a result. Even with clear skies and open lines of sight, it can take minutes before it’s able to start recording your activity — and it’s safe to say that your riding buddies probably won’t be happy about it.

The onboard optical heart rate monitor doesn’t work as well, either (although given the so-so performance of the Vivoactive HR, that’s not saying much). And unfortunately, you’re stuck with it as Fitbit equips the Surge with Bluetooth for wireless sync capability, but there’s no option for connecting any other sensors, such as a more accurate and consistent EKG-based chest strap.

The heart rate data from the Fitbit Surge's optical sensor was somewhat disappointing.
The heart rate data from the Fitbit Surge’s optical sensor was somewhat disappointing.

Differences aside, both devices can be configured to wirelessly upload ride data automatically to sites such as Strava, and the Surge does so especially quickly. Not surprisingly, both of the associated apps provide similar information as far as riding is concerned, including a map of your route, a variety of speed, distance, and heart rate statistics, and — of course — the ability to share those activities with anyone willing to listen. Both store quite a lengthy history of rides, too.

The Li-ion rechargeable batteries in both will last long enough for most rides (10 hours for the Surge and 13 hours for Vivoactive HR, claimed, plus roughly a week in everyday mode for both), and both have identical 5 ATM water resistance ratings (although Fitbit doesn’t recommend that the Surge be used for swimming).

Neither offers on-screen, turn-by-turn navigation, either (and even breadcrumb-type, preprogrammed route guidance is only possible on the Vivoactive HR via a third-party app). And although both record elevation data via built-in barometric altimeters, that information is only revealed after the ride has been uploaded to your smartphone, not during a ride.

Overall, both devices will suffice for basic route recording and displaying essential pieces of data, and of the two options discussed here, the Garmin Vivoactive HR would certainly be my pick. Nevertheless, if your list of wants and needs on the bike extend beyond the necessities — and if you don’t have any need for the multisport capabilities that both of these offer — it’d be best to look elsewhere.

Garmin Vivoactive HR vs. Garmin Vivoactive HR, off the bike

It’s only when you consider both devices’ non-cycling-specific functions that they become more appealing, and given their shared price points and shared target markets, it’s no surprise that both the Fitbit Surge and Garmin Vivoactive HR are very similar both in terms of hardware and features.

In terms of day-to-day activity tracking, both provide the metrics many have come to expect from these types of devices, including total steps, distance, and flights of stairs taken, current heart rate, calories burned, and impressively detailed analyses of your sleep behavior that not only look at how long you were asleep, but also the quality of that rest.

But once again, there are a number of substantial differences.

Both devices will display incoming text messages and phone calls (provided they’re paired with a smartphone running the required apps), but the Vivoactive HR ups the ante by showing a preview of incoming emails as well as pending calendar items, too. Both display current heart rate, but only the Vivoactive’s heart rate screen also provides the most recent resting heart rate and daily high and low values.

In fact, all of the Vivoactive’s activity screens are generally packed with more data, such as multi-day histories and graphs that are surprisingly detailed given the relatively tiny screen. All of that information is collected by the Surge, mind you, but it’s only accessible via the smartphone app.

Once again, it wasn’t long before the Garmin became the device that I also preferred between the two on a day-to-day basis. It’s more comfortable to wear long-term, and it provides more useful information that’s also easier to access. Also, whereas Fitbit is predominantly focused on activity and fitness when it comes to its wearables, Garmin has bundled a more diverse collection of functions into the Vivoactive HR. This not only includes controls for its own devices (such as the VIRB action camera, Varia on-bike radar system, and Varia bike lights), but also more general-purpose apps such as weather, calculators, basic mapping, and other utilities through Garmin’s impressively diverse Connect IQ app community.

Fitbit also has its own app community to enhance the functionality of the Surge as needed, but they’re all invariably still geared toward fitness, activity, and wellness.

The missing link when it comes to fitness trackers and cycling

It is perhaps worth mentioning that, by nature, fitness trackers may only have limited appeal to enthusiastic cyclists. After all, most are designed to help sedentary people become more active, whereas most avid cyclists are constantly striving for more time to ride.

Even so, it shouldn’t be ignored that activity trackers — especially more advanced models such as the two discussed here — still collect a wealth of useful data 24 hours a day, 365 days a year (barring the time required for recharging). Resting heart rate and sleep data, for example, can provide valuable information in terms of recovery and general health as they relate to training.

The Garmin Connect smartphone app (at left) is built more with cycling in mind. In contrast, the Fitbit app is clearly aimed more at general fitness.
The Garmin Connect smartphone app (at left) is built more with cycling in mind. In contrast, the Fitbit app is clearly aimed more at general fitness.

Unfortunately, no fitness tracker (or associated software package) is bridging the gap between merely recording and displaying that information, and translating it into something more useful.

“For the active person, the current generation of fitness trackers just provides another data channel for them to manage in their everyday life,” said cycling coach Jon Tarkington of Teton Consulting, based in Boulder, Colorado. “For most people, it seems to exceed their personal bandwidth because most of them don’t track anything that’s an easily actionable item.”

Both devices track your sleep patterns. The information is interesting, but neither app provides any guidance in terms of what you should do with the data.
Both devices track your sleep patterns. The information is interesting, but neither app provides any guidance in terms of what you should do with the data.

In other words, it’s neat to see a plot over time of your resting heart rate, but how many people know what to do with that information even if they notice a change? If there’s a sudden disruption in your sleep patterns, does that signify anything in terms of your training?

“The devices definitely have potential in helping to make sure your easier days are easier and then managing your harder days, both in life and in your activity, but I don’t necessarily the current software and the current user interfaces capitalize on that yet,” Tarkington said. “[The data from wearables] would finally give coaches access to what those people are doing the other twenty-some odd hours that they’re not on their bike. Strava, TrainingPeaks, Today’s Plan, GarminConnect — there are a lot of things out there that all give you a really good analysis of the time you’re on your bike or doing an activity, but as soon as you stop, you stop. You lose that tracking capability. [Fitness trackers] have the potential to fill that in, and then as time goes on, and as your data sets get bigger and bigger, then you can start creating much more actionable items out of that — combining things like resting heart rate, sleep, what kind of exact training stress they’re under, but what its composition was.”

“Watching your resting heart rate is not rocket science,” he continued. “The variability isn’t going to be huge for an athlete, but you’re going to be able to see those periods where your training load gets really high and you’re having trouble handling it, or life is really stressful, and maybe you should be dropping your training load. Or when you get sick — that’s been one of the bigger ones I’ve noticed in myself and some of the athletes I have that use these — it’s a great precursor for that. You can see it spike — three or four beats per minute — in the days before it turns into a full-blown illness. When you plot that out for a really fit individual, it’s really significant.”

Resting heart rate is a metric that could be extremely valuable, but only if it's analyzed correctly. None of the wearables covered here provide direct information to the wearer in terms of how resting heart rate reflects on training and recovery.
Resting heart rate is a metric that could be extremely valuable, but only if it’s analyzed correctly. None of the wearables covered here provide direct information to the wearer in terms of how resting heart rate reflects on training and recovery.

From the outside, it may seem like integrating data from fitness trackers and other wearables into one of those established training web sites would be easy to do, and according to Tarkington, it should be — in theory. In reality, though, the way the data is collected doesn’t play well with how those sites are currently designed to operate.

“It’s not that complicated for any of those sites to micro-analyze a ride file and actually merge the two to the point where you get, ‘yes, you should go ahead and do training X, or no, you should steer to training Y.’ The data is already being stored on a server somewhere, but it’s easier said than done. The data set is different than what most of those sites are set up to use. They typically pull records that are based on every second of recording or the .fit format or .gpx/.tcx file format, and these won’t necessary export in that. You’ve to to pull out what you want, and it comes in a very raw format.”

Even then, says Tarkington, an experienced coach would still have to know how to analyze that everyday data to determine its effect on a training schedule.

“Someone’s got to sit there and look at the bigger picture of, this is what their training is, this is what their tracker is saying, these are the words coming out of their mouth, this is what they’re telling me, and put those pieces together to make the educated choice.”

Those two sets of data may not be seamlessly joined together just yet, but Tarkington certainly thinks it could be done — and that it could very well put human coaches like himself out of work.

“The scary part about all of this is that, as those platforms work towards that, it creates the potential for really, really good artificial coaches. Your artificial coach still won’t help you through a divorce, but I definitely see that sort of artificial intelligence being the next step with all of this. The machine will be able to make the decision just as well as a human could.”

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