Background: The peak oxygen uptake (VO₂peak) test is the gold standard for cardiorespiratory fitness. However, the test is demanding, requiring sophisticated apparatus for measuring the oxygen uptake. Peak work rate (WRpeak) testing is a promising substitute for peak VO₂peak testing. However, there is a paucity of research conducted to determine reference values (RVs) for WRpeak.

Methods: The database from the LowLands fitness registry was used, containing data from health checks from apparently healthy subjects among various professions. Exercise tests were performed using a cycle ergometer and a calibrated metabolic cart. Analysis was executed on 3463 subjects, 2868 male and 595 female. Reference values with corresponding centiles were developed using the LMS method.

Results: VO₂peak and WRpeak where highly associated with Pearson’s correlation of 0.9 (p = .001). Weight, height, maximum heart rate, and the respiratory exchange ratio had a positive significant effect (p < .001) on WRpeak, and age a negative significant effect, in both males and females. The following formulas were computed for RVs:

Conclusions: WRpeak can be used as a substitute for VO₂peak when a respiratory gas-analysis system is not available. This study provides RVs for WRpeak and WRpeak/kg in a healthy Dutch/Flemish adult population using cycle ergometry. Further research is needed to obtain RVs for elderly subjects, specific diseases, ethnicities and ergometers.