Alpha Release - v0.1.0

Optimize for burning
fat or carbs.

Desktop software for real-time metabolic analysis with power meter integration. See exactly when you burn fat, when you burn carbs, and where your thresholds really are. Not estimated. Measured.

OpenSpiro — Session Replay with VO2, VCO2, RER, heart rate, power, and fuel mix

Everything you need

Test your metabolism. Train in the right zones. See your progress over time.

Live Dashboard

VO2, VCO2, RER, heart rate, and power at a glance in real time.

Guided Test Protocols

Step-by-step preparation checklists, individual watt thresholds adapted to the athlete, and automatic stage progression. No more invalid results from poor test setup.

Power Meter & Smart Trainer

Garmin Rally, Favero Assioma, Wahoo KICKR, Tacx and more - live power, cycling dynamics, and torque data directly in your metabolic test. No more manual data merging.

Data Export

Export sessions as CSV or JSON for external analysis and reporting.

Multi-Device Support

Works with Calibre Bio, VO2Master, and more. Connect any BLE or ANT+ heart rate monitor and power meter. Built-in calibration tools for each device.

Free & Local

Free VO2max testing, no account required, no external servers. Your data stays on your machine. Additional protocols and features coming soon.

Download now

Free VO2max testing with full power meter integration. Available for macOS and Windows. No account required.

Compatible with Calibre Bio and VO2Master portable VO2 analyzers. Works with all ANT+ and Bluetooth power meters and smart trainers.

Frequently Asked Questions