The product
From watching a number
to knowing what to do.
VO₂max is the maximum amount of oxygen your body can use during intense exercise—a measure of cardiorespiratory fitness.
Wearables made the number visible. But people in my research were seeing it stall or decline, without knowing what training to do next. The app connects training protocols, guided sessions, and progress tracking.
Test the demand
Would people try it?
I turned the research into a PRD and built a web MVP with Cursor: protocols, logging, and progress. Sharing it on Reddit brought the first sign-ups.
Next, I needed to know who was joining.
Learn who joins
Onboarding had to listen,
not just explain.
My early flow educated users, then offered optional setup. I made essential profile questions part of the experience.
Now I knew my audience: mostly men around 40, low to moderately active, with 65% focused on longevity.
Ship to learn
What people do
decides what stays.
Email outreach got no responses. Session replays and analytics became my feedback loop: adoption, engagement, and retention.
Train
Make the next workout obvious.
A direct path to training.
The first version focused on the active protocol and starting a session.
Track
Let tracking do less asking.
Too much to manage.
Separate categories and manual forms made users responsible for every entry.
3× more users logging sessions Reported after the native tracking changes.
The next problem
Get to the first workout.
The product showed stronger retention among people who completed a workout. My next focus is the gap between onboarding and that first session.
Different cohorts, measured over 30 days. The next target is 15% overall retention.