Where is the next stage for wearables that moved from smartphones to smartwatches?
Brian Lynch, who developed hardware at Apple for about 24 years, focused on "fingers," not the wrist. Lynch is a former engineer-turned-executive who worked across product design, advanced materials, simulation, and hardware at Apple. He spent years experiencing Apple's hardware development that raises performance, design, and usability together by packing multiple parts and technologies into limited space. The next destination he chose was the smart ring company Oura. It is a company that places sensors, a battery, and a processor inside a ring far smaller than a smartwatch with a screen to measure health data.
Founded in Finland and headquartered in San Francisco, Oura attracted more than $900 million (about 1.25 trillion won) in investment in Oct. last year, receiving a valuation of $11 billion (about 15 trillion won). According to market research firm Omdia, it accounted for 74% of global smart ring shipments in the first half of 2025, and its 2025 revenue reached $1 billion (about 1.4 trillion won). It will release the new product "Oura Ring 5" in Korea on the 25th.
Lynch, Oura's senior vice president of hardware engineering, met with ChosunBiz on the 18th and said, "The best wearable is a product the user actually wants to keep wearing." The future of wearables he envisions is not a device that piles on notifications. It is closer to a "quiet health companion" that measures health signals day and night without demanding the user's attention. The following is a Q&A with Lynch.
—What was the decisive reason for leaving Apple for Oura?
"I was deeply drawn to Oura's products and mission. Oura aims to shift healthcare from reactive to preventive by providing tools that help people better understand their health and detect warning signs early. I thought it was a mission worth investing my career in."
—Which experience at Apple most influenced your current role?
"How to collaborate with people of diverse expertise. To make the Oura Ring, you must organically connect science, algorithms, firmware, and electrical and mechanical engineering. No single area can work independently. Our team's goal is to build hardware accurate enough to trust and use, and comfortable enough to wear every day."
—Why are smart rings drawing attention as the next-generation wearables?
"The best wearable is a product the user wants to keep wearing. If you often take it off to charge or it's uncomfortable to wear during sleep, you miss important health data. The Oura Ring is designed to feel natural and comfortable like jewelry. Once charged, the Oura Ring can be used for up to a week. When accurate measurement is combined with 24-hour data, you can grasp an individual's baseline and changes that deviate from that baseline."
—What advantages are there to measuring on the finger rather than the wrist?
"Accuracy starts with the measurement site. On the finger, arteries are close to the skin surface. On the wrist, signals can be affected by body hair, cartilage, and skin tone, but on the finger you can obtain relatively strong and consistent pulse signals. It is also advantageous for measuring temperature changes. Another strength is that people are used to wearing rings."
—The Oura Ring 5 is 40% smaller than its predecessor. How did you maintain performance and battery?
"We tried not to compromise on anything. We shrank components close to their physical limits while putting as much technology as possible into a small space. Conversely, as the ring became thinner, the LEDs moved closer to the skin, which helped get better signals. Miniaturization, accuracy, battery, and comfort are a single inseparable design problem. It is an unavoidable reality that lithium battery capacity declines over time. That's why we look not only at how long you can use it after a full charge, but also at whether it can sustain performance close to the initial level for years."
—What is the most important health signal?
"Photoplethysmography (PPG) signals are key. But increasingly important is how multiple sensors work together rather than any single sensor. Algorithms combine each signal and find changes and patterns in long-accumulated data. As Machine Learning advances, the likelihood of obtaining information that is hard to find with individual sensors is growing."
—Why present complex biometric data in simple forms like a sleep score?
"Data are useful when you can understand what they mean to you. Rather than applying the same criteria to everyone, we compare daily measurements to each user's usual baseline. When multiple indicators change together, we can guide users to prioritize rest. It is more important to understand trends over time than a single daily score."
—Where will wearables' competitiveness be decided: hardware or AI?
"It's difficult with only one. If accurate sensing data are the objective foundation, AI turns them into trends and analyses that users can act on. If either is missing, the other's value cannot be fully realized. Our goal is to combine accurate sensing, scientific validation, and personalized algorithms so users can trust both the data and the guidance."
—Can smart rings replace smartwatches?
"Rather than competing head-on, they serve different roles. Smartwatches focus on notifications, apps, and daytime interactions. By contrast, the Oura Ring has no screen and no vibration. It focuses on measuring health data all day, including during sleep, without the user being conscious of it, and providing meaningful information when needed."
—Samsung Electronics has released the Galaxy Ring, and Apple's market entry is also being mentioned. What is Oura's technical strength?
"It is hard to predict a competitive landscape based on something that has not happened yet (Apple's market entry). That said, Oura has long focused on the single field of smart rings and has advanced its products and technology. Experts in science, algorithms, hardware, mechanical and electrical engineering, and firmware work closely together. Our early accumulated experience and expertise in this field, and our high level of focus, are strengths."
—What is Oura ultimately aiming for?
"It is to shift healthcare from treating disease after it occurs to a preventive focus. Going forward, wearables can serve as warning signals that detect changes deviating from an individual's baseline early. This is not about replacing medical professionals but about enabling faster consultations and interventions. What matters is not collecting more data, but accumulating accurate data over a long period and turning it into actionable information tailored to the individual."