Product leader, fitness operator, and AI founder. Former Head of Product at Freeletics, now building Titan Health.

Stephen is the founder of Titan Health and writes most of the Titan blog. He builds performance analytics from Apple Watch data for the same audience he has shipped products to for a decade: people who take training seriously and want software that respects it. He also founded Fuel, an AI nutrition coaching app that sends the meals you log to Titan through Apple Health.
From 2017 to 2020 he led product, design, research, content, and subscription monetization as Head of Product & Design at Freeletics, where his teams helped the digital fitness app surpass 50 million users worldwide across 100+ countries, with 70% week-one training activation. That stint — owning every surface that touches habit formation in a fitness app — is the operator lens behind every article here.
After Freeletics he grew Productboard 5x to $50M+ ARR as Senior Director of Product Management (2020–2022), reshaping the product from SMB/PLG-darling to enterprise roadmap software adopted by 6,000+ companies. Since 2022 he has been co-founder and CEO of Klu.ai, an LLM infrastructure platform used by thousands of AI teams, which is why the AI features in Titan feel less hand-wavy than most.
Earlier he ran global UX programs at Amazon (2016–2017) for cross-border eCommerce, led mobile investing design at Capital One (2014–2016), and spent a decade (2003–2014) running Smoov, a boutique design studio shipping work across consoles, desktop, mobile, and web. He speaks regularly at EU CPO Conference, SXSW, La Product Conf, and Product Led Alliance. Verifiable on SMW.ai, LinkedIn, and Speaker Deck.
How Apple Watch turns 1 to 10 effort ratings into a 7 day versus 28 day training load, the session RPE research behind it, and where Titan's heart rate load agrees and parts ways.
Median HRV by age and sex from 84,772 healthy adults, why RMSSD, SDNN and recording windows never match, and why your own baseline is the reference.
What WHOOP 5.0 and Apple Watch measure, how each scored against lab ECG and polysomnography, three-year costs at September 2026 prices, and what Titan adds to an Apple Watch.
28 articles on the Titan blog, newest first.
