The dubious science of biological age tracking

The premise is deceptively simple: if you work out and eat right, your body should function like that of a younger person. Companies like Whoop, Oura, Garmin, and Withings have built entire marketing narratives around these physiological age scores. Yet, the data remains wildly inconsistent across devices. Victoria Song, a senior reviewer at The Verge, reports that her own health trackers offer conflicting narratives about her physical state, with some claiming her heart is years younger than her chronological age while others suggest her vascular health is lagging behind.

These algorithms often rely on superficial inputs—such as blood flow captured via a 30-second selfie mirror or sleep patterns tracked by a mattress topper—to make broad claims about biological decay. Because these metrics are proprietary and lack standardized clinical validation, they function more as gamified feedback loops than diagnostic tools. Relying on these numbers to measure longevity ignores the nuance of medical science, transforming personal health into a shifting, often contradictory, statistical guessing game.