Research

Mixed

High-Intensity Interval Training (HIIT) is more effective for fat loss and muscle retention in younger obese adults (18-30 years), whereas Moderate-Intensity Continuous Training (MICT) is preferred for middle-aged (31-40) and older (41-60) adults due to better adherence and sustainability.

If you are under 30 and obese, HIIT may offer faster fat loss and muscle retention. If you are over 30, prioritize Moderate-Intensity Continuous Training (MICT) like brisk walking or cycling, as it is equally effective for fat loss but easier to stick with and safer for joints.

ModerateQualifiesMEDIUM confidence
HIIT was found to be most effective for younger individuals (18–30 years), promoting fat oxidation and muscle retention. In middle-aged adults (31–40 years), both HIIT and MICT yielded similar benefits, with MICT preferred due to better adherence. In older adults (41–60 years), MICT provided a more sustainable strategy for fat reduction and muscle preservation.
Sławomir Jagsz et al. · Journal of Clinical Medicine · 2025

Why this rating

Systematic review of 22 studies, but notes high variability and lack of definitive conclusions due to heterogeneity.

Source

The Effectiveness of High-Intensity Interval Training vs. Cardio Training for Weight Loss in Patients with Obesity: A Systematic Review

Sławomir Jagsz et al. · Journal of Clinical Medicine · 2025

DOI 10.3390/jcm14041282

systematic_review · n=508Cited 6×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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