### I Tested a Garmin, Apple, Google, and Coros Watch During a 20-Mile Marathon Preparation: The Results Were Informative
Over the weekend, I participated in a 20-mile marathon training event equipped with not just one, but **four fitness trackers**: the **Garmin Fenix 8**, **COROS PACE Pro**, **Apple Watch Ultra 2**, and **Google Pixel Watch 3**. While I felt somewhat absurd with so many devices strapped to my wrists, the insights I collected were undeniably worthwhile, despite the odd stares. This trial enabled me to assess the precision and reliability of these well-known fitness watches across numerous metrics, from heart rate to running power, yielding intriguing and significant findings.
### Why Use Four Watches?
As a fitness aficionado and tech tester, I frequently don multiple smartwatches during my runs to evaluate their precision. This time, my goal was to see how these four devices—each a leading participant in the fitness smartwatch arena—would fare in a long-distance setting. The **Run the Parkway** event, featuring nearly 1,000 runners, presented an ideal chance to evaluate their performance in actual running conditions.
Normally, I tend to limit myself to two watches, but on this occasion, I decided to challenge myself with four. The brisk 40ºF weather initially helped me cover my tech-laden wrists with long sleeves, but as the temperature climbed, I had to roll them back, revealing my unconventional setup to inquisitive spectators. Regardless of the awkwardness, I collected valuable data, summarized in the table below.
### Post-Run Data from Four Fitness Trackers for the 20-Mile Challenge
| **Category** | **Apple Watch Ultra 2** | **COROS PACE Pro** | **Garmin Fenix 8** | **Google Pixel Watch 3** |
|————————–|————————-|——————–|——————–|————————–|
| **Distance** | 19.92 miles | 20.11 miles | 20.08 miles | 20.19 miles |
| **Pace** | 9:38/mile | 9:33/mile | 9:34/mile | 9:31/mile |
| **Ascent** | 675 feet | 709 feet | 676 feet | 680 feet |
| **Avg. / Max Heart Rate** | 168 bpm / 179 bpm | 168 bpm / 182 bpm | 168 bpm / 182 bpm | 167 bpm / 181 bpm |
| **Running Power** | 250 W | 264 W | 351 W | Unknown |
| **Calories** | 3,016 kcal | 3,332 kcal | 2,773 kcal | 3,190 kcal |
| **Training Load** | Unknown | 781 | 362 | 565 |
| **Steps** | 31,958 | 32,247 | 32,196 | 32,192 |
| **Cadence** | 162 spm | 163 spm | 162 spm | 162 spm |
| **Stride Length** | 1.02m | 1.03m | 1.03m | 1.03m |
| **Vertical Oscillation** | 9cm | Unknown | 8.6cm | 7.7cm |
### Data Consistency Across Brands
Even with the distinct algorithms, sensors, and technologies, I was struck by how **consistent** the data appeared from all four watches. Metrics such as **distance**, **pace**, **heart rate**, **steps**, **cadence**, and **stride length** all showed minimal deviation. This reliability demonstrates that contemporary fitness watches, no matter the brand, are becoming more dependable for key fitness metrics.
For instance, all four watches accurately captured my **heart rate**, maintaining a difference of only 1 bpm across the board. Likewise, the **step count** and **cadence** statistics were almost identical, which is noteworthy considering the watches were positioned differently on my arms.
### Areas Where Fitness Watch Data Varies
While the essential metrics aligned well, some distinct variances emerged in other aspects, particularly in **running power**, **training load**, and **calories burned**.
#### Running Power
Running power is a relatively novel measurement that assesses the energy expended while running. It’s derived from factors such as speed, cadence, and vertical oscillation. However, the outcomes among the watches displayed surprising discrepancies. For example, Garmin recorded my running power at **351 watts**, while COROS and Apple measured it at **264W** and
