Effect of High-Intensity Interval Training vs. Moderate-Intensity Continuous Training on Fat Loss and Cardiorespiratory Fitness in the Young and Middle-Aged a Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 36981649 · doi:10.3390/ijerph20064741
What was done
A systematic review and meta-analysis of randomized controlled trials was conducted across seven databases through October 2022 to evaluate high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) in young and middle-aged adults. Outcomes analyzed for within-group and between-group changes included body mass, body mass index, waist circumference, percent fat mass, fat mass, fat-free mass, and cardiorespiratory fitness (CRF).
What was found
From 1,738 retrieved records, 29 randomized trials were included. Within-group analyses showed both HIIT and MICT produced significant improvements in body composition and CRF, but neither improved fat-free mass. Direct between-group comparisons found HIIT yielded significantly greater improvements than MICT for waist circumference, percent fat mass, and peak oxygen uptake (VO2peak). The abstract reports no numerical effect sizes, confidence intervals, or p-values.
Why it matters
This review shows HIIT matches or slightly exceeds MICT for reducing waist circumference and percent body fat while enhancing cardiorespiratory fitness, offering a time-efficient alternative for young and middle-aged adults.
Limits
The abstract does not provide numerical effect estimates, confidence intervals, or total participant counts. The authors note the magnitude of clinical benefit may be limited, and outcomes were modulated by age, obesity status, intervention duration (>6 weeks), frequency, and specific HIIT work intervals.
Cited by
- supports The greatest cardiorespiratory fitness benefit is derived from high-intensity training rather than moderate-pace walking.