Background/Aim Cardiorespiratory fitness (CRF) is a strong determinant of morbidity and mortality. In athletes and the general population, it is established that high-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. This is a systematic review and meta-analysis to quantify the efficacy and safety of HIIT compared to MICT in individuals with chronic cardiometabolic lifestyle diseases.

Methods The included studies were required to have a population sample of chronic disease, where poor lifestyle is considered as a main contributor to the disease. The procedural quality of the studies was assessed by use of a modified Physiotherapy Evidence Base Database (PEDro) scale. A meta-analysis compared the mean difference (MD) of preintervention versus postintervention CRF (VO₂peak) between HIIT and MICT.

Results 10 studies with 273 patients were included in the meta-analysis. Participants had coronary artery disease, heart failure, hypertension, metabolic syndrome and obesity. There was a significantly higher increase in the VO₂peak after HIIT compared to MICT (MD 3.03 mL/kg/min, 95% CI 2.00 to 4.07), equivalent to 9.1%.

Conclusions HIIT significantly increases CRF by almost double that of MICT in patients with lifestyle-induced chronic diseases.