A Wearable Startup Pushed Blood Pressure as Wellness and Helped Prompt a Rule Change, Its CEO Says

Four years ago, Will Ahmed, the chief executive of the wearable company Whoop, decided his wristband should estimate blood pressure without the usual arm cuff.

The problem was working out a usable blood pressure reading from the signals the sensor picks up. No product on the market could then get an accurate reading that way, so Whoop set out to see if it could be done.

The first step was data, gathered by running a study at huge scale fast. Whoop invited members to take part in a study on stress, sleep, and blood pressure. About 70,000 people enrolled, uploading cuff readings every day for weeks alongside the continuous physiological data Whoop already collected.

That combination gave Whoop a large training set, and Ahmed said it produced a very powerful algorithm for estimating blood pressure. That blood pressure feature became a test of what health gadgets can say.

The Food and Drug Administration regulates products that offer a medical diagnosis. Products that do not offer a diagnosis fall into a separate category called wellness. Heart rate had a clear split. Tracking it for exercise or sleep was wellness, while using it to detect an irregular heartbeat or predict a heart attack required regulation. For blood pressure, the agency's position was that any measurement had to be medical.

Ahmed disagreed. He pointed to research showing that blood pressure affects stress, sleep, and overall well being, and said there was a clear lane for a feature focused on those connections rather than diagnosis. The company launched the feature.

The FDA responded with a warning letter saying the feature needed to be regulated. The disagreement played out in public, but Ahmed said the company stuck to its guns through a long process.

The agency has since updated its guidelines to allow wellness uses for blood pressure. Ahmed said he believes Whoop's case helped prompt the change, along with feedback from the industry. The blood pressure insights feature remains available to consumers.

Ahmed pursues two routes for new features. For medical uses, the company seeks FDA clearance through clinical trials, as with its finger-on-device electrocardiogram cleared through the FDA's 510(k) route, a faster review for devices similar to ones already sold. For other uses, it brings features to market faster as wellness applications, as with blood pressure.