Validation of VO_2max Prediction Using International Formulae for Young Saudi Men

Objectives: In this study, we aimed to assess the maximal oxygen uptake (VO_2max) of young, healthy, non-athletic Saudi men using maximum graded exercise with instant breath-by-breath analysis and to compare this value to the predicted VO_2max by international formulae. Methods: In this cross-sectional study, 88 young non-athletic normal-weight Saudi subjects were recruited from Eastern Province of Saudi Arabia with mean age (21.3 ± 1.5 years), weight: (64.7 ± 7.5 kg), height: (172.3 ± 6.1 cm) and body mass index: (21.8 ± 2.1). All subjects were interviewed and examined for eligibility, after which they performed maximum graded exercise testing on a treadmill to obtain VO_2max. The predicted VO_2max was also generated using the following formulae (Edvardsen, Fairbarns, FRIENDS, Hansen, and Jones). Results: The mean measured VO_2max was 41.9 ± 7.2 ml/kg/min. While the predicted VO_2max using the formulae were: Edvardsen = 66.8 ± 7.9, Fairbarns = 64.1 ± 4.7, FRIENDS = 53.5 ± 2.2, Hansen = 42.8 ± 0.54, and Jones = 50.9 ± 5.1 ml/kg/min. There was a significant difference between all the predicted VO_2max and the measured one using the paired t-test (P < 0.001), except for the Hansen's predicted value (P = 0.212). The effect size index (Cohen's d) for the comparison of Hansen's VO_2max and measured VO_2max was trivial and equal to 0.13. The Bland-Altman test showed good agreement between the measured and Hansen's predicted VO_2max. Conclusion: This study demonstrated the mean VO_2max value of young, healthy, and non-athletic Saudi men. This value was lower than Western values, which might be due to low physical activity or racial differences. Most international formulae overestimate the VO_2max in this population, except for the Hansen equation. Therefore, Hansen's predicted VO_2max might be the best available reference value for the diagnosis and prognosis of young Saudi individuals undergoing maximum exercise testing.