Jul 21, 2025 · 1h 5m · how-i-built-this
WHOOP: Will Ahmed
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
In this episode of How I Built This, WHOOP founder Will Ahmed recounts how he turned his collegiate struggles with athletic overtraining into a pioneering continuous health-monitoring wearable. Ahmed details how he navigated relentless investor skepticism, tech-giant competition, and high-stakes business pivots to build an industry-leading human performance brand.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. Guy holds 37.6% of the talking time here. How this is scored →
Guy as informed peer 3.8 Guest teaching 4.4 Guest disagreement 1.2 Guy pushing back 1.9
speaking balance: gold is Guy, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 58:15 Will condemns Amazon's shameless copycat product
Will forcefully vents his outrage at Amazon for blatantly knocking off the WHOOP device and an Amazon PM tweeting 'WHOOP, there it is'.
Hardest push from Guy ▶ 17:25 Guy calls Will's initial fundraising pitch an affrontGuy directly challenges Will's credentials, pointing out that asking for investor capital as an inexperienced 22-year-old was bordering on offensive.
Biggest teaching moment ▶ 29:36 Will breaks down photoplethysmography sensor physicsWill provides a thorough scientific explanation of how optical light reflection interacts with skin pigment, hair, and non-periodic movement.
Guy holds their own ▶ 59:58 Guy analyzes why litigating against Amazon would be suicidalGuy provides strategic analysis demonstrating why pursuing patent litigation against Amazon would drain startup capital versus focusing on product and brand.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | Guy as informed peer | Guest teaching | Guest disagreement | Guy pushing back | Why |
|---|---|---|---|---|---|---|
| Harvard Athletics and the Squash Team Experience | 4 | 6 | 1 | 2 | Guy questions why overtraining is considered negative for a young college athlete. Will educates Guy on the physiological difference between productive overreaching and chronic overtraining. | |
| Physiological Research and Deconstructing Medical Equipment | 5 | 6 | 0 | 1 | Will explains the three clinical measurement tools he researched (PSG, ECG, chest straps) and the importance of slow-wave sleep. Guy demonstrates familiarity with sleep labs and chest straps like Polar. | |
| Exploring Optical Sensors and Drafting the MIT Business Plan | 4 | 6 | 1 | 2 | Guy asks about early market trackers like Fitbit and Jawbone and early lab skepticism. Will explains why step counters were physiologically inadequate and how light sensors solved the measurement challenge. | |
| Founding Bobo Analytics and Facing Pitch Rejections | 5 | 4 | 3 | 5 | Guy challenges Will's audacity as an inexperienced college senior asking for money, calling it almost an affront. Will pushes back by framing the single-minded focus and availability of a 22-year-old as an asset. | |
| Assembling the Core Team and the Hamburg Flight | 3 | 3 | 1 | 2 | Will narrates assembling early co-founders and his impromptu flight to Hamburg to recruit designer Martin Oberhauser. Guy expresses amazement at the boldness of flying overseas on pure intuition. | |
| Mid-Show Break and Transition to 2012 Graduation | 3 | 5 | 0 | 1 | Following a mid-roll transition, Will describes their clumsy initial wired prototype and explains why heart rate variability (HRV) was chosen as the baseline metric for bodily recovery. | |
| Perpetual Early Fundraising and Developing Wireless Hardware | 4 | 7 | 1 | 1 | Will educates Guy on optical sensor physics, explaining why darker skin tones, body hair, and non-periodic movement created massive signal noise for photoplethysmography. | |
| The Threat of Big Tech and the Flawed Nike FuelBand | 4 | 5 | 3 | 2 | Guy brings up investor fears about the Nike FuelBand. Will recounts a hostile investor who told him he was doomed to fail, then explains why Nike's product was fundamentally flawed. | |
| Rebranding to WHOOP and Overcoming Startup Exhaustion | 3 | 2 | 0 | 1 | Will explains the collegiate origin of the name WHOOP and candidly reflects on his extreme personal burnout and anxiety during the early multi-million dollar fundraising rounds. | |
| Targeting Elite Trainers to Reach Superstar Athletes | 3 | 4 | 1 | 2 | Guy questions how a tiny startup could secure megastars like LeBron James and Michael Phelps without endorsement money. Will details his strategy of seeding personal trainers like Mike Mancias. | |
| Pro League Adoption and Committing to a Screenless Device | 3 | 5 | 1 | 2 | Guy inquires about competitive pressure from the Apple Watch and why WHOOP resisted adding a display screen. Will explains that avoiding a screen was vital for 24/7 continuous wear and focus. | |
| Direct-to-Consumer Launch and the Problem of Slow Sales | 4 | 3 | 1 | 4 | Guy presses on why consumer sales stalled five years into the company despite athlete endorsements. Will readily acknowledges his early business naivety and pricing mistakes. | |
| Mid-Show Break and Setup for the Business Model Pivot | 3 | 4 | 1 | 1 | Will explains the pivotal shift from a $500 one-time hardware purchase to a pure SaaS subscription model and why slow initial sales prevented catastrophic operational failure. | |
| Amazon Alexa Fund Diligence and Operating on Fumes | 3 | 3 | 1 | 2 | Will recalls Amazon's Alexa Fund conducting extensive diligence before passing, leaving WHOOP operating on under three months of runway for an 18-month stretch. | |
| Navigating Cash Constraints Without Taking Down Rounds | 6 | 4 | 4 | 2 | Will vents about Amazon copying WHOOP with the Halo band and reveals the defiant note printed on WHOOP circuit boards. Guy reinforces the wisdom of avoiding a costly lawsuit against Amazon. | |
| Elite Athlete Investors and Expanding Human Healthspan | 3 | 3 | 0 | 1 | Guy asks about expanding product lines beyond a single wristband and balancing luck versus hard work. Will discusses WHOOP's mission around human healthspan and maintaining long-term vision. |
Statements from this episode (26)
Ahmed: Overtraining prevents bodily recovery and mimics symptoms of sickness
“There's a distinction between overreaching and overtraining. Overreaching is where you're pushing your body a little too far, but in the days that follow, your body can bounce back. And overtraining is where you extend your body through such a long period of t…”
Ahmed: College athletic programs focus on practice while ignoring daily recovery
“Well, when I thought about what it meant to be a college athlete, I realized there was so much focus on what are we doing during the three hours that were four hours that were practice or training, but there was really not a lot of discussion around how you tr…”
Ahmed: Understanding recovery requires monitoring time outside training
“Well, the immediate thing that I realized is that to understand recovery, you have to understand all the time outside of training. And once you kind of opened your aperture to that idea, you realize, well, maybe training is just a piece of this puzzle.”
Ahmed: Tracking step count does not measure actual physiological stress
“I didn't think that steps answered anything about the strain recovery equation that we talked about before, which is to say that How much, you know, stress you're actually putting on your body is a different question than how much you've moved your arm.”
Ahmed: Computing inevitably evolves from desktops to laptops, pockets, and on-body wearables
“Computers over the course of my lifetime had gone from being on your desk to on your lap to in your pocket, and inevitably it seemed to me they were going to become on your body.”
Ahmed: WHOOP's founding plan spanned athletes, consumers, then medicine
“The original idea was we were going to start with athletes, and then eventually we were going to build a product for everyone, and then eventually we'd go into medicine.”
Ahmed: The advantage of backing 22-year-old founders is a lack of distractions
“And the advantage to betting on a twenty-two-year-old is they don't have a lot else going on.”
WHOOP's Ahmed: Data visualization is critical to wearable health businesses
“The way that we were going to visualize the data was actually going to end up becoming one of the most important characteristics of the business.”
Ahmed: Baselining daily HRV reveals human recovery and stress states
“If you can measure this thing and baseline it to a human, you could understand in any given moment the state of their body. Is your body at peace? Is it recovered? Is it stressed? And it also became obvious if you could measure heart rate variability during a …”
Ahmed: WHOOP raised $400K to build its wireless second prototype
“That's where the following prototype, which came, you know, maybe six months after that, and we'd raised another 400 grand. That prototype was able to do it without all the shenanigans of a wire and you know, a computer attached to your arm and so forth.”
Ahmed: Optical heart rate monitoring struggles with darker skin and body hair
“The challenge to heart rate monitoring is the darker the skin, the harder it is, the hairier the skin, the harder it is, and the more non-periodic motion, the harder it is, and if you're outdoors, that's harder than indoors.”
Ahmed: WHOOP skipped a screen to prioritize sensor data collection
“We didn't have a high resolution screen. In part because we put all of our resourcing towards data collection.”
Ahmed: Nike made a fatal mistake designing FuelBand as a step counter
“The way in which they were wrong at assessing the story I was telling versus the strategy that Nike was pursuing was that Nike made, in my opinion, a fatal mistake with their product. They made a product that all of their best athletes would never use. It was …”
Ahmed: WHOOP was rejected by 95% of VCs during early fundraising
“I was strung out, and at that point, you know, going to VCs and getting rejected by 95% of them.”
Ahmed: WHOOP raised ~$10M by late 2014 and ~$25M by mid-2015
“Yeah, we had raised ten million dollars probably total by the end of 2014, and then we had probably raised twenty five million total by mid 2015.”
Ahmed: WHOOP reached LeBron James by seeding devices with personal trainers
“And the secret to getting to them, just to say it was to find people in their lives that had a big influence on them that no one else knew. It turned out in 2015, the personal trainer was a relatively unknown person in a professional athlete's life. And it als…”
Ahmed: LeBron James and Michael Phelps were initially paying WHOOP customers
“We had no relationship with him. We had no relationship at the time with Michael Phelps either, and many of these athletes, I mean, they were essentially just a buyer of the product.”
Ahmed: WHOOP initially priced its consumer wearable at $500
“And maybe most importantly, we were selling the product for 500 dollars.”
Ahmed: The wearables market is plagued by poor long-term user retention
“The wearables industry, just to say it, is a market that's been plagued by engagement, which is to say someone buys a Fitbit, and then three weeks or three months later, it's in a drawer.”
Ahmed: Selling 100,000 units of a first hardware product is a mistake
“I meet hardware founders, and they talk a lot about How their first product is going to sell a 100,000 units in the first year. And I tell them that's actually the wrong goal. You really want your first product or your second product that goes to the consumer …”
Ahmed: Amazon's Alexa Fund passed on investing after extensive product diligence
“Yeah, we spent a lot of time with them, and they included their product team in the diligence, and then they ultimately did not invest in Whoop, to our surprise.”
Ahmed: WHOOP survived on under three months of runway for 18 months
“And that 18 month stretch of like beginning of 2017 to mid 2018 whoop was on fumes. I mean, we never had more runway than three months for an 18 month period of the company.”
Ahmed: WHOOP has never done a down round in its history
“You know, remarkably in the company's history, we've never done a down round.”
Ahmed: Amazon copied WHOOP with Halo, tweeting 'whoop, there it is'
“They knocked the product off. There's no question. And by the way, it was so egregious that one of the lead product manager from Amazon, when it came out, posted on Twitter, whoop, there it is announcing the new Amazon Halo.”
Ahmed: WHOOP printed 'Don't bother copying us' on its 4.0 circuit boards
“And so I wrote on every Ford auto circuit board. Don't bother copying us. We will win.”
Ahmed: Rory McIlroy, Cristiano Ronaldo, and Eli Manning Invested in WHOOP
“Rory McIlroy, Cristiano Ronaldo, Virgil van Dyke, Eli Manning, Larry Fitzgerald, and for me, like, I've gotten to make friends with a lot of these, you know, global superstars, and they've offered a lot of good advice to me personally, and also to the business…”