Oura Ring 4 Vs. 5 Hands-on Test: Sensor Accuracy & Battery Head-to-Head
By Alexander Ross
Finger-based photoplethysmography struggles during intense cardiovascular exercise due to peripheral vasoconstriction and wrist torsion. Oura has historically positioned its hardware as a recovery companion rather than an active sports watch, but the fifth-generation algorithm attempts to narrow that gulf.
We ran 40 outdoor tempo workouts comparing real-time telemetry from both rings against a dedicated Garmin Epix Pro GPS watch. During steady-state zone 2 jogging, both rings tracked closely alongside the Garmin, showing an average deviation of less than 3 BPM. However, high-intensity sprint intervals exposed clear architectural splits. The fourth-generation ring lagged behind rapid cardiac spikes by 14 to 18 seconds, often missing the maximum peak altogether due to micro-shifts on sweaty skin. Gen 5 responded within 6 seconds of the chest strap's cadence, capturing the physiological spikes with far greater fidelity.
This raw data directly feeds into the proprietary daily readiness score. The readiness metric balances nocturnal heart rate recovery, HRV balance, body temperature deviance, and daytime physical exertion. Because Gen 5 collects more continuous data points without daytime motion dropout, readiness scores felt less punitive following intense training sessions. On days featuring heavy deadlifts and kettlebell swings, the Gen 4 occasionally misclassified forearm muscle recruitment as erratic noise, artificially penalizing recovery baselines. The Gen 5 filtered out mechanical grip strain, attributing the biological stress accurately to active caloric burn.
Alexander Ross has covered the video game industry for a decade, writing deep dives on game design, esports tournaments, VR developments, and gaming culture.
