Evaluating maximal oxygen uptake in exercise-based cardiac rehabilitation

Purpose Maximal oxygen uptake (VO2max) is a strong, independent predictor of both all-cause and disease-specific mortality, making it a key health and performance marker for individuals with heart disease. While cardiopulmonary exercise testing is the gold standard for determining VO2max, its use in primary healthcare settings remains underexplored. This study aims to evaluate standard criteria for assessing VO2max in individuals enrolled in cardiac rehabilitation.Methods A cross-sectional study was conducted in a primary healthcare setting. Participants who referred to exercise-based cardiac rehabilitation underwent a cycle ergometer exercise test to determine VO2max. The primary validation criterion was the presence of a VO2 plateau, defined by cut-offs of ≤50 and ≤100 mL O2/min. Secondary criteria included respiratory exchange ratio, rate of perceived exertion, and maximal heart rate.Results Among 93 participants, 88% reached a VO2 plateau using the ≤100 mL cut-off. Additionally, 61% met at least two secondary criteria, indicating maximal effort.Conclusion In primary healthcare cardiac rehabilitation, a cut-off of ≤100 mL may be suitable for identifying a VO2 plateau. For those not reaching a plateau, maximal effort can be assessed using RER ≥1.15 and RPE ≥17 as criteria.