Self-Directed High-Intensity Interval Versus Moderate Continuous Training on Cardiometabolic Health in Metabolic...

Area of Science:

• Exercise Physiology
• Hepatology
• Cardiorespiratory Fitness

Background:

• Metabolic dysfunction-associated steatotic liver disease (MASLD) management guidelines recommend exercise.
• The optimal exercise modality for MASLD patients remains undetermined.
• Previous research has not directly compared HIIT and MCT for MASLD cardiorespiratory and liver fat outcomes.

Purpose of the Study:

• To compare the effects of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MCT) on cardiorespiratory fitness and hepatic steatosis in patients with MASLD.
• To determine if exercise intensity influences liver fat reduction in MASLD patients.
• To assess the impact of different exercise modes on metabolic parameters.

Main Methods:

• A randomized trial involving patients with ultrasonography-confirmed MASLD (formerly NAFLD).
• Participants were assigned to either HIIT (n=46) or MCT (n=49) for 24 weeks, performing treadmill training thrice weekly in free-living settings.
• A non-randomized observation group (OBS; n=20) was included for comparison. HIIT involved 5 cycles of 4-min intervals at 80%-90% peak oxygen consumption (V̇O2peak) with 3-min recovery, while MCT involved 30-40 min at 60% V̇O2peak.

Main Results:

• Both HIIT and MCT significantly reduced hepatic steatosis compared to the OBS group (p < 0.05), with no significant difference between the exercise modalities.
• HIIT demonstrated significantly greater improvements in peak oxygen consumption (V̇O2peak) compared to both MCT and OBS (p < 0.05).
• Both exercise groups showed increased minute ventilation and carbohydrate utilization at moderate-to-high intensities versus OBS (p < 0.05).

Conclusions:

• Exercise participation, rather than intensity, appears to be the primary driver for reducing liver fat in MASLD.
• HIIT offers superior benefits for improving cardiorespiratory fitness in MASLD patients compared to MCT.
• Both HIIT and MCT are effective in reducing hepatic steatosis, highlighting the importance of regular physical activity for MASLD management.