Whoop CEO Will Ahmed on Health Data and HRV

Twice in one week, a man's wrist told him something was wrong before his body did. His breathing rate crept up by two counts a minute. His skin ran two degrees hotter. Nothing hurt yet. By the following Sunday night he was in chest pain, driving himself to an Austin emergency room at one in the morning. Tests found lung inflammation pressing on his heart, not a heart attack, but a warning his device had already sounded two days earlier (10:17). The man was Jason Calacanis, co-host of the podcast All-In, and the device was Whoop, a screenless fitness band worn by the guest he was interviewing: founder and CEO Will Ahmed.

Ahmed started building Whoop in 2012 as a Harvard student fascinated by one obscure measurement: heart rate variability, or HRV, the tiny gaps in time between heartbeats. Back then nobody could track it around the clock. Fourteen years later, Whoop has collected more than 50 billion hours of continuous physiological data (00:00) from a membership Ahmed expects to hit 4 million by the end of the year (02:25). It took twelve years to sign the first million members, then eighteen months for the second, then six months for the third (02:14). Scale, in this business, came late and then all at once.

From a Five Hundred Dollar Gadget to a Dollar a Day

Whoop did not start as a subscription. In 2017 it sold the band outright for 500 dollars, a one time hardware purchase aimed at elite athletes. Ahmed's team noticed something odd: people who bought it wore it constantly, but not enough people were buying it (03:36). So the company tore up its own business model, dropped the upfront price, and moved to a membership of 15 to 30 dollars a month (02:37). The shift did more than change the price tag.

"When you're a subscription business, you become really obsessed with your existing members, arguably more so even than new members." — Will Ahmed [04:45]

That obsession reorders incentives. A hardware company needs a reason to sell someone a new gadget every year, whether or not the gadget is actually better. A subscription company needs the old gadget to keep getting smarter through software, because the same device has to earn its monthly fee for years. Whoop's answer has been to keep stacking features onto bands already on people's wrists: an ECG sensor cleared by the FDA, blood pressure estimates, a longevity score Whoop calls Healthspan, and an AI coach members can ask questions.

The three numbers most members check every morning are sleep, recovery, and strain (07:18), but the one Ahmed considers the deepest signal is HRV. Counterintuitively, more variability between heartbeats means a healthier, more adaptable body.

"The more variability in time between successive beats of the heart, the healthier your overall system is operating." — Will Ahmed [14:41]

HRV tends to fall with age: people in their twenties often sit between 80 and 100, a number that drifts to around 70 in the thirties, 50 in the forties, and down into the thirties or lower by the fifties and sixties (16:28). Holding that number flat over years, Ahmed argues, is itself a sign of good health, which is why Whoop treats HRV less as a snapshot than as a trend line worth defending (16:49).

The company's more startling claims involve catching illness before a person feels sick. Whoop flagged Calacanis's chest inflammation through a two breath jump in respiratory rate, normally one of the most boring, stable numbers the body produces (10:38). Ahmed described other cases: a member whose resting heart rate spiked to 120 or 130 beats per minute overnight turned out to have stage four Hodgkin lymphoma (13:39), and another whose steady HRV around 100 suddenly dropped to 50 turned out to have testicular cancer (16:49). None of these are diagnoses. They are anomalies that sent people to a doctor sooner than they otherwise would have gone. Ahmed's longer bet is that Whoop's data set, now including uploaded blood tests and medical records alongside the physiological stream, can eventually spot a hidden lab abnormality without a lab test at all.

"Through physiological signals, we might be able to predict that a biomarker is out of range without actually measuring the biomarker itself." — Will Ahmed [20:25]

Roughly half of Whoop's members fill out a daily journal logging alcohol, meditation, meal timing, and more than a hundred other habits (23:40), which the app then correlates against recovery scores. Calacanis, checking his own data live, found a warm bath added 7 percent to his recovery (26:44), while Ahmed noted alcohol cost him 9 percent. The company's blunter population level finding: eating within three hours of bedtime hurts sleep and recovery across virtually everyone, because the body is still digesting during the first hours it should be resting (28:05).

That same journal now tracks GLP-1 weight loss drugs, a feature Whoop added as the medications went mainstream. Ahmed's concern is specific: about half the weight lost on a GLP-1 can be muscle rather than fat if a person is not careful (33:15), which can leave someone thinner but frailer. Whoop's GLP-1 tracker nudges members toward a daily step target, two strength sessions a week, protein, and hydration, and Ahmed points to anecdotal reports that creatine supplementation helps preserve muscle for people on the drugs (33:35).

The FDA's Line Between Wellness and Medicine

Not every feature gets to ship quietly. Four years ago Whoop set out to measure blood pressure from the wrist, a genuinely hard signal processing problem with no accurate consumer solution on the market. The company recruited 70,000 members into an internal study, collecting daily cuff readings to train an algorithm against its existing physiological data (37:33). When Whoop launched the resulting Blood Pressure Insights feature as a wellness tool rather than a medical one, the FDA disagreed and sent a warning letter, arguing blood pressure monitoring had to be regulated as a medical device regardless of intent (39:46). Whoop kept the feature live through the dispute, and the FDA has since updated its guidance to allow wellness applications for blood pressure, a shift Ahmed credits partly to the case (40:06). The company separately holds FDA medical clearance for its ECG feature, which it treats as a genuinely different regulatory category (40:58).

Underneath the regulatory fight is a business model argument Ahmed is happy to make explicit, especially against bigger rivals who sell advertising.

"You are not the product, Jason. Like, you're... the membership is the product." — Will Ahmed [42:52]

Whoop does not sell member data, and its revenue comes entirely from subscriptions rather than ads, which Ahmed frames as the reason the company has earned the right to hold so much sensitive health information in the first place (42:30).

The episode closes on a smaller, stranger kind of proof. LeBron James, the basketball star now with the Philadelphia 76ers, has worn Whoop for 11 years, since before the company had a formal relationship with any athlete at all (47:41). He was one of the first hundred people ever to put one on. Whoop is now naming him a global ambassador, not because it paid him to try the product, but because an all time great kept wearing an unproven gadget from an unknown company for over a decade before anyone asked him to. That is the kind of data point no algorithm generates. It just accumulates, quietly, the same way the 50 billion hours did: one wrist, one night, at a time.