Building a Low-Cost Portable VO2 Max Mask

Maximal oxygen consumption more commonly known as VO₂ max is the gold standard indicator of cardiorespiratory fitness and a stronger predictor of all-cause mortality than traditional health risk factors such as smoking, diabetes, and hypertension. Despite being recognized as a clinical vital metric by the American Heart Association, there are no accurate low cost measurement devices commercially available for the masses. Gold standard commercial metabolic carts remain inaccessible due to their $30,000 - $50,000 cost. This thesis presents the design, implementation, and validation of a low-cost, portable VO₂ max measurement system consisting of a custom 3D-printed Venturi tube design for airflow measurement, three off-the-shelf sensors (differential pressure, electrochemical oxygen, and NDIR carbon dioxide), an ESP32 microcontroller with Bluetooth Low Energy transmission, and a Python-based logging and analysis pipeline. The system incorporates a BLE protocol that accommodates differing sensor sampling rates, while a mixing-chamber approach addresses the slower response times of low-cost sensors. Instrument-level validation confirmed all sensors perform within specifications: gas sensor verification demonstrated correct response direction, plausible magnitude, and repeatable baseline recovery, while the differential pressure sensor combined with the custom venturi tube provided plausible results without calibration. The complete system costs $222 which is a 10- to 100-fold cost reduction compared to commercially available systems. This thesis establishes a fully documented, open-source platform ready for calibration and human subject testing pending IRB approval.

Author dc:creator

• Shashwat Sinha (24399410)

• Engineering, Electronics and Electrical
• Engineering, Biomedical

Statement dc:rights

• In Copyright

DOI dc:identifier

https://doi.org/10.25417/uic.32993843.v1

OAI identifier oai:identifier

oai:figshare.com:article/32993843