Is low-volume high-intensity interval training a time-efficient strategy to improve cardiometabolic health and body composition? A meta-analysis

The present meta-analysis aimed to assess the effects of low-volume high-intensity interval training (LV-HIIT; i.e., ≤5 min high-intensity exercise within a ≤15 min session) on cardiometabolic health and body composition. A systematic search was performed in accordance with PRISMA guidelines to assess the effect of LV-HIIT on cardiometabolic health and body composition. Twenty-one studies (moderate to high quality) with a total of 849 participants were included in this meta-analysis. LV-HIIT increased cardiorespiratory fitness (CRF, SMD = 1.19 [0.87, 1.50]) while lowering systolic blood pressure (SMD = −1.44 [−1.68, −1.20]), diastolic blood pressure (SMD = −1.51 [−1.75, −1.27]), mean arterial pressure (SMD = −1.55 [−1.80, −1.30]), MetS z-score (SMD = −0.76 [−1.02, −0.49]), fat mass (kg) (SMD = −0.22 [−0.44, 0.00]), fat mass (%) (SMD = −0.22 [−0.41, −0.02]), and waist circumference (SMD = −0.53 [−0.75, −0.31]) compared to untrained control (CONTROL). Despite a total time-commitment of LV-HIIT of only 14%–47% and 45%–94% compared to moderate-intensity continuous training and HV-HIIT, respectively, there were no statistically significant differences observed for any outcomes in comparisons between LV-HIIT and moderate-intensity continuous training (MICT) or high-volume HIIT. Significant inverse dose–responses were observed between the change in CRF with LV-HIIT and sprint repetitions ( β = −0.52 [−0.76, −0.28]), high-intensity duration ( β = −0.21 [−0.39, −0.02]), and total duration ( β = −0.19 [−0.36, −0.02]), while higher intensity significantly improved CRF gains. LV-HIIT can improve cardiometabolic health and body composition and represent a time-efficient alternative to MICT and HV-HIIT. Performing LV-HIIT at a higher intensity drives higher CRF gains. More repetitions, longer time at high intensity, and total session duration did not augment gains in CRF.