Vigorous- Versus Moderate-intensity Exercise to Reduce Liver Fat in Adults With Obesity and NAFLD

Summary

Non-alcoholic fatty liver disease (NAFLD) arising from obesity has become a global health concern. Although exercise is a cornerstone approach for managing NAFLD, detailed exercise prescription guidelines are unavailable. According to World Health Organization (WHO) recommendations, 1 minute of vigorous-intensity physical activity can achieve equivalent health benefits to 2 minutes of moderate-intensity physical activity. It is not known whether this relationship is applicable to exercise prescribed as an adjunct therapy in NAFLD treatment. The answer has public health implications because people living with NAFLD can potentially opt for safe higher-intensity exercise requiring less of a time commitment, whereas those in older age groups or with comorbidities, for whom vigorous exercise is unsuitable, can adopt a moderate-intensity regimen of longer duration to acquire equivalent therapeutic outcomes. Adults with obesity and NAFLD will be randomly allocated to a supervised vigorous- or moderate-intensity walking group or usual care control group. Each exercise group will receive a 16-week intervention comprising three walking sessions weekly, whereas the usual care group will receive general health education as the attention control. The per-session walking time will be 25 minutes for the vigorous group and 50 minutes for the moderate group, equating to the same weekly exercise volume and caloric expenditure for each group according to the WHO's minimum physical activity recommendation. Outcome measures, including liver fat, visceral and body fat, body anthropometry, intervention adherence, psychological measures, health-related quality of life, medication usage, adverse events, habitual physical activity, and diet, will be examined by assessors blinded to the group allocation at baseline, 16 weeks (post-intervention), and 42 weeks (26-week post-intervention follow-up). Data will be analyzed by generalized estimating equations and linear contrasts. The proposed study will provide evidence on the presumed equivalent benefits of vigorous- and moderate-intensity exercise, with a follow-up period allowing assessment of the efficacy, safety, adherence, and sustainability of each. The findings will inform practitioners of the role of exercise intensity in reducing liver fat and refine the exercise guidelines for NAFLD patients.

Conditions

• Obesity
• NAFLD

Interventions

OTHER

Usual Care Control Group

Subjects in the usual care control group will receive health education as the attention control. The program will consist of eight 150-minute bi-weekly sessions covering major health issues relating to general health and NAFLD, to be obtained from publicly accessible resources from the Hong Kong Department of Health. Health education information on non-communicable diseases (e.g., cancers, diabetes, coronary heart diseases, obesity, and mental illness), infectious diseases (e.g., COVID-19), and a healthy lifestyle (e.g., balanced diet, physical activity, good sleep, tobacco use, alcohol cessation, and stress management) will also be distributed to the subjects in the exercise groups through recorded presentation videos and leaflets/pamphlets during the first 16 weeks.

OTHER

Moderate-intensity Exercise Intervention

The walking time in each session will be 50 minutes for the moderate-intensity group. The overall weekly exercise volume for the two groups will be the same based on total energy expenditure, as per the WHO's physical activity recommendation (150 minutes of moderate-intensity physical activity weekly is equivalent to 75 minutes of vigorous-intensity physical activity weekly). Five minutes of walking at a normal pace will be included for warm-up and cool-down.

OTHER

Vigorous-intensity Exercise Intervention

The walking time in each session will be 25 minutes for the vigorous-intensity group. The overall weekly exercise volume for the two groups will be the same based on total energy expenditure, as per the WHO's physical activity recommendation (150 minutes of moderate-intensity physical activity weekly is equivalent to 75 minutes of vigorous-intensity physical activity weekly). Five minutes of walking at a normal pace will be included for warm-up and cool-down.

Sponsors & Collaborators

• The University of Hong Kong

  lead OTHER

Principal Investigators

• Parco M Siu, PhD · LKS Faculty of Medicine, The University of Hong Kong

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

69 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-05-23

Primary Completion

2026-10-31

Completion

2027-01-31

Countries

• Hong Kong

Study Locations