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High-intensity running improves fat and carbohydrate metabolism in obese adults
Last reviewed: 09.08.2025
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A team of scientists led by Dr. Emily Chen from the University of Toronto (Canada) published in Applied Physiology, Nutrition, and Metabolism the results of a randomized controlled trial showing that a 12-week course of high-intensity interval training (HIIT) significantly improves metabolic flexibility, insulin sensitivity, and glucose tolerance in overweight adults.
Key Results
- Metabolic flexibility increased significantly in the HIIT group:
- Resting RER decreased by 0.07 (p < 0.01), indicating a better switch to fat oxidation.
- RER during exercise increased by 0.10 (p < 0.01) - more efficient use of carbohydrates during work.
- Insulin sensitivity (M-value) in the HIIT group increased by 25% (p < 0.05), while there were no changes in the controls.
- Glucose tolerance improved: AUC of OGTT decreased by 12% (p < 0.05).
- Fat mass: visceral fat decreased by 8%, total fat mass by 5% (both p < 0.05) without loss of muscle mass.
“Our study shows that a HIIT protocol of just three sessions per week can rapidly restore key metabolic parameters in overweight individuals,” says Dr. Chen.
Health implications
The effectiveness of HIIT in improving metabolic flexibility and insulin sensitivity makes this type of exercise particularly valuable for the prevention and treatment of metabolic syndrome and type 2 diabetes. Short-term but intense workouts are suitable even for busy individuals and clinics with few resources for long-term programs.
Prospects and Recommendations
- Incorporating HIIT into lifestyle recommendations for overweight patients.
- Further research into the optimization of exercise frequency and duration and the mechanisms underlying metabolic changes.
- The ability to combine HIIT with dietary and medicinal interventions to maximize metabolic improvement.
Thus, HIIT training is a quick and affordable way to restore normal fat and carbohydrate metabolism, strengthen insulin sensitivity and reduce the risk of developing diabetes and related complications.