The world's most in-depth and scientific reviews of outdoor gear

How We Tested GPS Sports Watches

By Larin McPeak ⋅ Review Editor
Tuesday November 26, 2019
A test editor putting devices (and his cardiopulmonary system!) through the paces on an uphill interval session.
A test editor putting devices (and his cardiopulmonary system!) through the paces on an uphill interval session.

To see how these products tracked our athletes' movements, we covered some ground. We logged thousands of miles, mainly on foot but also while biking and swimming. Whether our feet were in running shoes, mountaineering boots, or barefoot on the beach, our testing was real-world and comparative. We would regularly wear and compare multiple watches on the same endeavor, but we also wore each one alone to focus our full attention on it.

Our team of diverse testers captured different perspectives on what makes an outstanding GPS watch. Our lead tester logged fifteen to twenty training hours a week and monitored virtually every one of her training and active hours with one or more of the products in this review. She ran trails with big elevation gains throughout northern California, ran a marathon in Frankfurt Germany with 14,000 participants and jogged through parks in China.

After this much use, we are experts on these watches and are excited to share the details with you.

Ease of Use


This category is absolutely essential to any GPS watch purchase. It measures the watches' capacity to meet their intended purpose. Sometimes one flaw in a watch can ruin the interaction with it and prevent the user from successfully acquiring the data that the watch was meant to provide. This category also includes how the watches interact with their software platforms, whether that be an app, a website or a program (or all three of these). If the syncing, data sharing and data presentation on the platform is difficult to operate, view or understand, then even if the watch is amazing, the program can ruin the user experience.

By simply using the devices, and sharing them with a diverse test team, we developed and distilled a significant body of user experience. We back up our opinions with years of experience and months of testing. To further clarify, the Ease of Use metrics deal primarily with the user interface, intuitive function and systematic observations over time.

One of our tests took us through the streets of Frankfurt  Germany in the Frankfurt Marathon.
One of our tests took us through the streets of Frankfurt, Germany in the Frankfurt Marathon.

Features


The absolute main discerning category that affects watch price is the number of features. We compared each product to a list of potential features. This list combines features included in each watch's hardware, software and their user platforms on your pc or app. Some devices can be customized further. The list of potential features we compared are timekeeping, GPS distance, and speed, GPS data recording, GPS navigation, step count, sleep tracking, built-in heart rate, compatibility with external sensors, dynamics, metrics, barometer, altimeter, thermometer, smartwatch functions and more.

Usually, it can be assumed that an increase in features on the watch and its platforms have a direct result on all other variables in our tests. Sometimes the effect on the other variables is positive, for example, some added features that pertain to metrics collection will enhance the accuracy but sometimes additional features will lower scores. A good example of this is when there are so many features that the watch becomes difficult to use or requires a lot of time investment to learn how to use it.

Accuracy


If the watch is inaccurate, the data is skewed and the watch is not completing it´s designed task. That said, no watch can be perfect. There are just too many variables to consider. This is why accuracy counts for less percentage in our award weighting. To evaluate accuracy, we had to repeat a lot of our test runs over and over again. We ran for weeks and weeks, repeating routes and running new routes, all while wearing one watch on each wrist and carrying one watch in each pocket. In this way, we were able to test the GPS accuracy of up to 4 watches simultaneously. We could also test the optical heart rate monitor of 2 watches at a time, wearing one on each wrist. We never placed more than one watch on each wrist and one watch in each pocket to keep the GPS antennas from interfering with each other.

We also tried to run over bridges and next to bodies of water as much as possible to see if the watches mapped us as swimming instead of running. Afterward the run, we compared the distances, elevations, and mapping data, all while considering the limitations and features of each watch (e.g., does it have a barometric altimeter, etc.).

We found that a snug fit is imperative to get an accurate heart rate reading. The watches that didn't fit our testers as well usually reported skewed heart rate results. We also used a chest strap heart rate monitor while using one or more of the watches as a stable comparison control. Chest heart rate monitors are considered more accurate and are not affected by a watch's fit on the wrist. We also used the watches to monitor our sleep so we could review our resting heart rates. Since we were lying still and not sweating, sleep testing offered a more controlled environment for heart rate measurement testing.

Ease of Set-up


Nobody has time to spend reading extensive manuals when they just received their shiny new watch! People want to put it on and go running! In order to measure Ease of Set-up, we noted how many steps were required, how clear the instructions are (including those on the device, in its app, or its paper manual), how intuitive the set-up was and the active and passive (i.e., syncing) time required. Set-up on GPS watches includes also the set up in the software platform and the syncing of the two. Sometimes updates need to be downloaded and these can literally take a half a day if there are enough updates.

Battery Life


Battery Life is mostly important to endurance athletes but it can also be frustrating to recharge your watch every day, even as a recreational athlete. A number of variables make it challenging to test the battery life of these GPS watches fairly. Battery life hinges on how you use these watches. There are two battery usage types that are important for athletes — normal use and activity usage. We tested normal use (some manufacturers call this "smartwatch usage") to find out how many days each watch stays charged when we run only a few hours a week and use it as a daily smartwatch, which included fielding random numbers of text notifications a day.

We tested activity use to determine how many hours each watch can last during a nonstop activity, like a race. To do this, we let each watch run tracking data from a full charge until it was empty to see which watch would make your 100-mile ultra without needing a charge, and which wouldn't. An ultra runner, cyclist or triathlete might need the battery to last during their activity for 10+ hours. A recreational athlete will require that the watch lasts several days as a smartwatch with interspersed training, for example, three days a week with one hour runs additionally to the normal watch usage.

Design


Design is mainly a function of size, fit, comfort, raw materials and the somewhat subjective factor of appearance. Larger watches will not fit all wrists. Smaller ones may fit all wrists, but they make it difficult to read the screen. We measured and weighed each one, and noted whether they are difficult to wear under typical running and athletic clothing and if size affected the fit, and thus the accuracy of the optical heart rate monitor.

Auf Wiedersehen! That is the end of our GPS Watch review. Time to run.
Auf Wiedersehen! That is the end of our GPS Watch review. Time to run.