Buzz
Smartwatches are highly effective at measuring running or walking distances outdoors. However, when used indoors, their readings often conflict with those displayed on gym treadmills. This inconsistency raises a common question—should we place our trust in the treadmill or the smartwatch?
The treadmill is the more reliable option in this scenario. It has a clearer understanding of your foot movements compared to a smartwatch. However, skepticism toward gym machine displays is understandable, especially given their notoriously unreliable calorie calculations.
Reasons Why Treadmills Outperform Smartwatches in Distance Accuracy
When assessing accuracy, it’s crucial to determine whether a device is directly measuring something or interpreting data to estimate. Here, the treadmill directly measures distance, whereas the watch relies on estimations. (Calories, being always interpreted, are inherently unreliable.)
Distance is straightforward: It’s the length of the treadmill belt that moves beneath your feet as you run. The treadmill calculates this by knowing the belt’s length and the motor’s speed, providing a direct measurement. (Technically, some interpretation exists due to potential changes in motor performance over time, which is why treadmill calibration is necessary. However, it remains highly accurate for our purposes.)
On the other hand, your watch sits on your wrist, making it impossible to track your foot movements directly. It estimates based on arm swings, correlating each swing to a step. Faster running increases arm swing intensity, allowing the watch to guess your speed and, consequently, your distance.
Tips for Achieving the Most Accurate Measurements
While neither method is flawless, the treadmill is far more reliable. A treadmill might have minor calibration issues, but it’s still closer to accuracy. A watch, however, merely guesses based on wrist movements. Personally, I’ve observed that my arm swings don’t vary significantly between fast and slow running paces.
During interval workouts on a treadmill using a Garmin Forerunner 265, I’ve noticed the watch often underestimates my speed during fast intervals. When it alerts me with a “Pace low” buzz, I can manipulate it by exaggerating my arm movements. However, this isn’t a reliable fix.
Rather than striving for precise watch readings mid-run, I rely on the following accurate metrics during treadmill workouts:
The treadmill’s speed during the session
The total distance recorded by the treadmill post-workout
Heart rate data from my watch (particularly when paired with a chest strap)
Time tracking from either or both devices (assuming they were started simultaneously)
I tailor my workouts accordingly. For heart-rate-based sessions, I let the watch take charge. (For instance, if Garmin suggests 32 minutes at 139 to 167 beats per minute, I follow its guidance without question.)
For speed- or distance-focused workouts, I manually control the treadmill. For example, running a quarter mile at 7.5 mph eight times requires adjusting the treadmill settings. Post-workout, I either calibrate the watch or edit the distance in my app to ensure accuracy.
