Smart ring battery life remains the ultimate engineering bottleneck in micro-wearables. Because a ring cannot house a bulky lithium pouch, power consumption must be curbed via ultra-low-power Bluetooth LE transceivers and power-efficient microcontrollers. The Oura Ring 5 pushes typical real-world runtimes up to 6, 8 continuous days, an improvement over the 4, 7 days recorded by Gen 4 users under full-featured SpO2 tracking conditions.
Real-world testing highlights how critical that extra day can be. Cosmopolitan editors tracked their recovery over twelve consecutive weeks following surgery, noting that the Gen 5 consistently cleared an entire workweek plus a weekend getaway without touching its magnetic charging dock. Less frequent charging cycles also reduce long-term battery degradation, extending the operational lifespan of the non-replaceable lithium-polymer cell over multiple years.
The Oura Ring 5 sizing kit has also expanded. Historical smart ring designs left individuals with very slender or unusually broad fingers without functional options. By expanding production tooling from size 4 up to size 15, Oura widened its addressable base. The Gen 5 plastic sizing rings reflect the flatter interior profile of the production hardware, meaning existing Gen 4 owners cannot rely solely on their previous sizing kit to pick a new model.
