The utilization of ventilatory threshold parameters for exercise prescription in exercise rehabilitation

Background Cardiac rehabilitation (CR) is the cornerstone in secondary cardiovascular disease prevention. However, there remains a significant variation in cardiorespiratory fitness (CRF) response to exercise training. Ventilatory threshold (VT) parameters, particularly the first (VT1) and second (VT2) ventilatory thresholds for determining exercise intensity, have recently emerged as reliable indicators in guiding exercise intensity prescription across clinical populations. Tailored exercise prescription based on individualised exercise intensity ranges derived from thresholds are thought to increase CRF response rates. This review aims to evaluate and synthesise what is known on threshold-based exercise prescription and its impact on cardiac rehabilitation. Methods A systematic literature review was conducted across multiple electronic databases, yielding 414 studies, which were narrowed down to 13 studies matching the review criteria and included in the analysis. Results This review included eleven studies that addressed either a sedentary, physically inactive, or at-risk (with obesity or metabolic syndrome) population and all showed significant improvement in VO2max among participants after aerobic training. However, only seven studies showed greater improvements in threshold-based exercise compared to standardised training. Additionally, for this population there were three studies demonstrating greater improvements in VO2 at VT after training among those utilising a threshold-based protocol. Among cardiac patients, the use of ventilatory thresholds for exercise prescription also demonstrated favourable outcomes though more nuanced. Two studies had focused on a population with cardiovascular disease and both showed significant improvements in VO2max and VO2VT after training with only one reporting superiority to heart rate-based training. Conclusion Threshold based assessment of exercise intensity differs from values derived from existing heart-rate based ranges recommended in guidelines. Tailored exercise prescription using personal thresholds appear to illicit positive changes in CRF both in absolute improvements though its superiority cannot yet be established due to limited available studies. Larger study cohorts are required to assess the latter and its feasibility in application on a population level.