Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max improvements: A Systematic review and Meta-Analysis of controlled trials

摘要

Background Enhancing cardiovascular fitness can lead to substantial health benefits. High-intensity interval training (HIT) is an efficient way to develop cardiovascular fitness, yet comparisons between this type of training with traditional endurance training are equivocal.\udObjective Our objective was to meta-analyse the effects of endurance training and HIT on the maximal oxygen consumption (VO2max) of healthy, young to middle-aged adults. \udMethods Six electronic databases were searched (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) for original research articles. A search was conducted and search terms included ‘high intensity’, ‘HIT’, ‘sprint interval training’, ‘endurance training’, ‘peak oxygen uptake’, ‘VO2max’. Inclusion criteria were controlled trials, healthy adults aged 18-45 y, training duration ≥2 weeks, VO2max assessed pre- and post-training. Twenty-eight studies met the inclusion criteria and were included in the meta-analysis. This resulted in 723 participants with a mean ± SD age and initial fitness of 25.1 ± 5 y and 40.8 ± 7.9 mL•kg-1•min-1, respectively. We made probabilistic magnitude-based inferences for meta-analysed effects based on standardized thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations (SDs) for baseline VO2max. \udResults The meta-analysed effect of endurance training on VO2max was a possibly large beneficial effect (4.9 mL•kg-1•min-1; 95% confidence limits ±1.4 mL•kg-1•min-1), when compared with no exercise controls. A possibly moderate additional increase was observed for typically younger subjects (2.4 mL•kg-1•min-1; ±2.1 mL•kg-1•min-1) and interventions of longer duration (2.2 mL•kg-1•min-1; ±3.0 mL•kg-1•min-1), and a small additional improvement for subjects with lower baseline fitness (1.4 mL•kg-1•min-1; ±2.0 mL•kg-1•min-1). When compared to no exercise controls, there was likely large beneficial effect of HIT (5.5 mL•kg-1•min-1; ±1.2 mL•kg-1•min-1), with a likely moderate greater additional increase for subjects with lower baseline fitness (3.2 mL•kg-1•min-1; ±1.9 mL•kg-1•min-1) and interventions of longer duration (3.0 mL•kg-1•min-1; ±1.9 mL•kg-1•min-1), and a small lesser effect for typically longer HIT repetitions (-1.8 mL•kg-1•min-1; ±2.7 mL•kg-1•min-1). The modifying effects of age (0.8 mL•kg-1•min-1; ±2.1 mL•kg-1•min-1) and work:rest ratio (0.5 mL•kg-1•min-1; ±1.6 mL•kg-1•min-1) were unclear. When compared to endurance training, there was a possibly small beneficial effect for HIT (1.2 mL•kg-1•min-1; ±0.9 mL•kg-1•min-1) with small additional improvements for typically longer HIT repetitions (2.2 mL•kg-1•min-1; ±2.1 mL•kg-1•min-1), older subjects (1.8 mL•kg-1•min-1; ±1.7 mL•kg-1•min-1), interventions of longer duration (1.7 mL•kg-1•min-1; ±1.7 mL•kg-1•min-1), greater work:rest ratio (1.6 mL•kg-1•min-1; ±1.5 mL•kg-1•min-1) and lower baseline fitness (0.8 mL•kg-1•min-1; ±1.3 mL•kg-1•min-1).\udConclusion Endurance training and HIT both elicit large improvements in the VO2max of healthy, young to middle-aged adults with the gains in VO2max being greater following HIT, when compared to endurance training.