Insights on health technology, privacy-first design, and the science behind smarter wearables.
Your sleep tracker tells you how badly you slept every morning. For a growing number of people, that number is the reason they can't sleep at all. The condition has a name: orthosomnia.
Most smart rings track your cycle by measuring skin temperature for a thermal shift around ovulation. The problem is the algorithm defaults to a 28-day cycle that fits about 16% of people. Here is what the clinical evidence actually says and where your temperature data ends up.
Every running watch and fitness tracker claims to estimate your VO2 max. But the number on your wrist and the number from a gas exchange analyzer are different things. Here is what the validation studies actually measure, and why your wearable is probably off by 10 to 15 percent.
A March 2026 Nature study found that sleep and temperature data from consumer wearables can detect diabetes with 73% accuracy. The sensors are already in your smart ring. The companies selling them are not using them for this.
Green-light PPG sensors in smart rings measure pulse by shining LEDs through your skin. Melanin absorbs that green light, which means your Oura or Ultrahuman reads your heart rate differently based on your skin tone. The research shows 30 to 60 percent signal degradation on darker skin. The industry does not talk about it. Pulsyn is building a ring that does.
You factory-reset your Oura before listing it on eBay. The buyer gets a clean ring. Your heart rate data from the last 18 months is still in their cloud.
Your wearable thinks sleep is a bank account. Sleep six hours instead of eight, and your app tells you you're 'two hours behind.' This is not how sleep works. Sleep is regulated by two biological processes that do not use arithmetic, and the idea that you can store or repay hours is a marketing fiction.
Your smart ring tells you to sleep at 9:30 PM because your heart rate dropped. But it does not know whether your brain produces melatonin at 9:30 PM or midnight. Chronotype, the genetic wiring that makes you a lark or a night owl, is ignored by every bedtime guidance feature on the market.
Oura calls it Readiness. Whoop calls it Recovery. Garmin calls it Body Battery. They all pull from the same three inputs. The names are different because the marketing departments are different. The math is nearly identical because the sensors are identical.
