Honest Review of the COROS Pace 4 (Scientific Test)
In a Nutshell
The COROS Pace 4 excels in GPS tracking for running and cycling, delivering super-consistent signals on par with top Garmin and Suunto models, making it a strong sports watch recommendation despite occasional sudden deviations. Heart rate accuracy is good for indoor/outdoor cycling (0.97 correlation) but middling for running (cadence lock issues) and poor for weightlifting/sleep stages, so pair with a chest strap or biceps monitor for precision training. Prioritize it for GPS/battery over all-rounders like Apple Watch or Pixel if sleep/HR aren't key; avoid for sleep tracking—opt for Whoop, Oura, or Eight Sleep instead.
These notes were generated by AI and may contain inaccuracies.
I've always enjoyed using COROS products like the Pace 3 or the Pace 4. Generally positive, though I point out problems with data accuracy. COROS products do well in sports watch testing. Surprised to be ghosted by COROS and hear they don't think there's an audience fit. Their privilege, makes business sense. Surprised since I worked well with them, personally disappointed. Not angry, just disappointed. Still open to samples. Review delayed because I purchased the Pace 4 with my own money after others got pre-release units.
I'm Rob, post-doc scientist specializing in biological data analysis. No data filtering. Show all data as is.
Collected data on COROS Pace 4. Start with heart rate tracking. Reference: Polar H10 chest strap.
Indoor cycling: Horizontal axis reference HR, vertical Pace 4 HR. Perfect agreement on blue line. Most points close. Few below or above. Correlation 0.97 (very good, >0.9 preferred, 0.95+ ideal).
Individual sessions: Generally good agreement. Minor delays in HR changes, nothing major. Some deviation at starts, but minor. Nothing changes training.
Compares to competition (all tested devices): Pace 4 in upper middle class. Zoom to ≥0.95 correlation: Close to Pace 3. Better devices: Apple Watches, some Huawei, Amazfit Helio strap on biceps, Vertix 2 (limited), Pixel Watches. All ≥0.95 good enough for indoor cycling.
Running harder. Scatter plot good but deviations, e.g., high HR detection possibly cadence lock.
Sessions: Some good. One bad intervals session: Pace 4 missed intervals, weird minor increases (cadence?). Others decent with minor deviations, some bad (unsteady, suspected cadence lock at 160 cadence vs lower HR). Correlation middle pack, close to Galaxy Watch, Pace 3 retest. Worse than Apple Watches, Amazfit Helio (biceps), Pixel Watch, Huawei, Polar Vantage (biceps), Garmin 410/165/570/970. Tested in cold (less blood flow downside). Not recommend for running without COROS HR monitor (biceps) or ECG chest strap.
Outdoor cycling harder. Plot good, points close to line.
Sessions: Mostly good, minor deviations. Compares well to competition. Close to COROS HR monitor (biceps), Pace 3. In second tier, better than many. Zoom ≥0.90: Close to Forerunner 570, Vertix 2S, COROS HR monitor. Best: Apple Watches, Pixel, Huawei. Good enough for purposes.
Sponsor note: Support via YouTube membership, affiliate links (Pace 4 Amazon, Whoop, Eight Sleep pod - favorite sleep device), Amazon purchases.
Correlation 0.8. Points below line at high HR (sets). Pace 4 misses peaks due to arm tension. Typical for wrist devices. Recommend chest strap (ECG) over wrist optical.
Overall HR mixed: Good indoor/outdoor cycling, poor running (cadence lock?), bad weightlifting. Pair with external HR monitor. GPS solid (later). Light watch. Recommend Runner app for custom plans/guidance (affiliate 2-week trial).
Debated mentioning interaction. No hard feelings. Explains less COROS content. Brands respond differently to data-driven reviews. Always show data as is, even for affiliates.
Reference: ZMachine EEG headband (silver standard, brain waves).
Confusion matrix (normalized %): Deep sleep 50% agreement (rest light/awake). Light 55% (confused with REM). REM 40% (mostly light). Sports watches struggle with REM.
Example nights: One poor sleep - deep mostly matched but extra deep detected. REM segments partially missed, extras detected.
Not recommend. Comparison: Poor, like Huawei. Garmin, Polar, Suunto better. Top 2025: Pixel/Google/Fitbit, Apple, Whoop, Oura Ring, Eight Sleep pod (best, mattress, cools/heats independently - great for couples/summer). Galaxy close.
Eight Sleep pod expensive, affiliate link.
Pace Pro similar performance (same sensor?).
Tested GPS cycling/running. Same circle/route multiple times, check overlap. Used most accurate mode.
Park Belvedere, Vienna. Left no interference, right wall (orange). Signals consistent left/right. Minor deviations near tourists/end.
Just near the end, there's a little bit of deviation, but compared to much of the competition, this is looking really good. Another run shows very consistent signals on the left. On top, a bit more deviation, possibly true due to dodging tourists. On the right, generally very good, though there are weird moments with sudden big deviations. Probably COROS accounts for this in the total distance. Except for those moments, it's some of the best performance seen.
Cycling outside can be harder due to faster speeds and city buildings interfering with signals. Tested consistency with five times cycling to work and five times back. For five cycles to work, signals are very good and consistent from the beginning. A little deviation in one signal, but pretty good. Very consistent here. More deviation than liked over here, okayish not great. Bit of deviation, but then super consistent afterward with signals very close. Not seen better results. Looking really good up until this point, still really good. Took a slightly different route, walked across crossroads—signal looking really good, little deviation in one, otherwise pretty good. Ends at different workspaces.
Five cycles back from work (SAM and Med Uni). Quite consistent, really good. Many devices struggle at the beginning needing time for accurate signal, but COROS Pace 4 did really well. Super consistent, little deviation influenced by buildings but still good. Bit more deviation than liked, but excellent around the roundabout where many devices struggle. Pretty consistent, bit of deviation but overall really good. Little deviation here, but compared to competition, honestly really good. Super consistent. Really happy with GPS tracking performance—on par with best from Garmin or Suunto.
For GPS tracking, really recommend the COROS Pace 4. Only small complaint: in runs, few moments of sudden big deviation then snap back. Otherwise super consistent, happy to use as sports watch.
Wouldn't use for sleep tracking. Pair with external heart rate monitor for running. For indoor and outdoor cycling, built-in HR probably good enough. If into training in different heart rate zones for accuracy, get ECG chest strap or biceps HR monitor—easier clean signal even with PPG sensor.
Solid performance as sports watch. Not absolute best for HR tracking in running, but GPS really good. Don't recommend for sleep stage tracking—get more all-round device like Pixel Watch (Android) or Apple Watch (iOS), though they lack COROS Pace 4's GPS performance and battery life.
Depends on priorities. Whoop strap: good battery life, sleep stage tracking, decent HR, but no screen or built-in GPS. Lots of nuance—no single best device, but a best for you. Weigh what's important.
Hope this helps decide on COROS Pace 4, Oura ring, Whoop strap, Eight Sleep pod, or anything else. Support via affiliate links below. If watched whole video, check Garmin 4970 or HLE pod videos.
Keep The Quantified Scientist in your library
Save the videos and channels worth coming back to, and find them again in one place.
