True VO2 Max — Cardio Fitness

True VO2 Max gives you lab-like cardio fitness insights using your Apple Watch — now indoors too.

Stop getting misleading VO₂ max drops from heat, humidity, altitude, smog, or tough outdoor conditions. We correct for real-world factors so you can trust your fitness trend. And with our first-of-its-kind Indoor Treadmill VO₂ Max, you can track cardio fitness even when you run inside.

No account required.

No ads.

▷ INDOOR TREADMILL VO₂ MAX

- Estimate VO₂ max from indoor treadmill runs

- Perfect for winter, rain, or night runs

- See indoor fitness changes clearly — without outdoor weather noise

▷ CORRECTED VO₂, ANY WEATHER

- Removes temperature, humidity, altitude, heat, cold, etc.

- Raw vs Corrected shown side-by-side

- Trust the trend, not the temperature

▷ SCIENCE-BACKED CORRECTIONS

- Research-based penalties for weather & elevation

- Transparent impact per condition

- Spot real changes vs. bad weather

▷ IMPACT RESULTS

- Automatic processing the moment you finish your workout

- Be first to see your real fitness trend — no more confusion

- See progress even when conditions make it look worse

▷ AUTOMATIONS

- Apple Watch sync

- Health app sync

- VO2 corrections, no manual input needed

▷ WHAT'S FREE?

- No ads

- Unlimited runs/workouts

- Corrected VO₂ max vs. weather

- Raw Apple Watch VO₂ max vs. Corrected VO₂ max

- Weather logging

- Record your activities

- Basic insights about your performance

▷ WHAT'S PLUS?

- Indoor Treadmill Watch app

- Instant weather capture as soon as you finish your workout

- Most accurate VO2 max correction every time

- Clear & transparent impact per weather condition

- Improve your VO₂ max with Full Insights

- Personalized performance takeaways

- And more

Try Plus free for 7 days. Cancel anytime.

▷ PRIVACY

- No account needed

- No tracking

- No ads

- No personal data collected

- No third-party SDKs

- All logged info (runs, corrected VO2 max, etc.) remains on-device

Not a medical device. True VO2 Max is for fitness and wellness only.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/