Key Points
- To describe the technological evolution, operating mechanisms, validity, and reliability of portable open-circuit spirometry systems against criterion standard methods.
- Evaluated 11 portable metabolic systems: Oxylog, Aerosport KB1-C, Cosmed K2, Cosmed K4RQ, Cosmed K4b2, MetaMax I, MetaMax II, Metamax3B/VmaxST, Medgraphics VO2000, Oxycon Mobile I, and Oxycon Mobile II.
- Summarized VO2 measurement validity against the Douglas bag method (DBM) and test-retest reliability across rest, submaximal, and maximal exercise conditions.
- Resting VO2 mean differences were within ±0.05 L/min for 10 of 11 devices, while exercise VO2 differences versus DBM spanned 0.01 to 0.29 L/min at submaximal and 0.01 to 0.36 L/min at maximal intensities.
- Reliability across exercise intensities demonstrated intraclass correlation coefficients ranging from 0.66 to 0.99 and coefficients of variation between 2.0% and 14.2%, showing no substantial difference between breath-by-breath and micro-proportional sampling technologies.
- Cosmed K4b2 and Oxycon Mobile II provided valid VO2 estimates within ±0.10 L/min of DBM across all conditions, whereas MetaMax3B slightly overestimated VO2 during maximal exercise.
Structured PICO
PPopulation11 portable open-circuit spirometry systems
IInterventionPortable open-circuit spirometry systems
CComparatorDouglas bag method (DBM)
OOutcomeValidity and reliability for measuring VO2surrogate
Most portable open-circuit spirometry systems provide valid and reliable estimates of VO2 compared to the Douglas bag method across various exercise intensities.