CPET-based HIIT for MAFLD

54 Participants aged 35-65 years with MAFLD will be randomized 1:1 to intervention or control. The intervention group will undertake home-based HIIT four times weekly for 8 weeks. Each session comprises 8 cycles with 30-second bouts at 80% peak VO₂ followed by 60-second recoveries at 50% peak VO₂. The control group do not take any types of exercise interventions. Standard care would be provided for both groups.

Inclusion criteria

Adults age 35~65 years Nonalcoholic fatty liver diagnosed by abdominal ultrasonography

In conjunction with at least one cardiometabolic risk factor:

• Overweight or Obesity: ≥ 24kg/m2，or waist circumference ≥ 90 cm in men and > 85 cm in women, or excessive body fat mass
• Prediabetes or type 2 diabetes mellitus: HbA1c ≥ 5.7%, or fasting plasma glucose ≥ 6.1mmol/L, or 2-h plasma glucose during OGTT ≥ 7.8mmol/L
• Plasma triglycerides ≥ 1.7 mmol/L (>-150 mg/dl) or lipid-lowering treatment
• HDL-cholesterol ≤ -1.0 mmol/L in men and ≤ -1.3 mmol/L in women or lipid-lowering treatment
• Blood pressure ≥ 130/85 mmHg or treatment for hypertension

Exclusion criteria

• Contraindications for Cardiopulmonary Exercise Testing
• The electrocardiogram (ECG) results during cardiopulmonary exercise testing (CPET) showed positive findings
• Receiving GLP-1 receptor agonists, SGLT-2i, or taking >2 antihypertensive/hypoglycemic/lipid-lowering/ antiarrhythmic drugs
• Taking dietary supplements (e.g., fish oil products, over-the-counter diet pills, meal replacements)
• Mental illness
• Other liver diseases
• Movement disorder related diseases and lower limb motor injury in the past 6 months
• Pregnant, lactating or planning to become pregnant in the near future