The Study
The Release of Lipolytic Hormones during Various High-Intensity Interval and Moderate-Intensity Continuous Training Regimens and Their Effects on Fat Loss.
This study shows that when obese young women did different kinds of intense workouts, they lost more fat than those who did slower, steady exercise. But it doesn't prove that the hormones released during the workouts caused the fat loss—just that both happened together.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists tested if super-short, super-hard workouts (HIIT) help obese young women lose more fat than longer, easier workouts (MICT), even if both burn the same total energy.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 555 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — losing 3–4% body fat percentage means a 150-lb person with 35% body fat drops to 31%, which is a noticeable and healthy change.
- 2After 12 weeks, HIIT groups lost 15–17% more body fat and 3–4% more body fat percentage than MICT.
- 3Epinephrine (a fat-burning hormone) spiked after HIIT but not MICT.
- 4VO2peak (fitness) improved more with HIIT.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of sports science & medicine
Year
2024
Authors
Xiangui Zhu, Jiao Jiao, Yu Liu, Hong Li, Haifeng Zhang
Related Content
Claims (6)
Twenty-minute high-intensity interval training sessions lead to more fat loss than forty-minute steady-state cardio sessions.
In obese young women, both high-intensity interval training and moderate-intensity continuous training raise growth hormone levels equally, and this increase does not explain why high-intensity interval training leads to more fat loss.
In obese young women, 12 weeks of high-intensity interval training reduces body fat mass and body fat percentage more than moderate-intensity continuous training, even when the total amount of work performed is the same.
In obese young women, short bursts of intense exercise cause a larger increase in epinephrine after the workout than steady moderate exercise, and the amount of epinephrine released does not change between the two most intense workout levels, while moderate exercise does not raise epinephrine at all.
After 12 weeks of sprint interval training, obese young women produce more epinephrine after exercise than they did before starting the training.
In obese young women, high-intensity interval training at 90% and 120% of maximal oxygen capacity increases maximal oxygen uptake more than moderate-intensity continuous training, regardless of fat loss.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.