12-Month Once-a-week HIIT Improves Body Adiposity and Liver Fat

The University of Hong Kong (HKU)

Status: Completed

Conditions: Central Obesity; Non-Alcoholic Fatty Liver Disease

Treatments: Behavioral: Usual Care Control; Behavioral: High-intensity Interval Training

Study type: Interventional

Funder types: Other

Identifiers

NCT03912272

RF-9835-NAFLD-001

Details and patient eligibility

About

Obesity and non-alcoholic fatty liver disease (NAFLD) are two related growing epidemics that are becoming pressing public health concerns. High-intensity interval training (HIIT) is a promising cost-effective and time-efficient exercise modality for managing obesity and NAFLD. However, patients with obesity and NAFLD are generally inactive and unfit, and might feel intimidated by the frequency of the prescribed HIIT (conventionally three times weekly). Previous HIIT studies, mostly over 2-4 month periods, showed that the participants could accomplish this exercise frequency under a controlled laboratory environment, but the long-term adherence and sustainability, especially in a field setting, remains uncertain. The situation is more unclear if we also consider those individuals who refused to participate possibly because of their overwhelming perceptions or low self-efficacy toward HIIT. Thus, logically, HIIT at a lower frequency would be practical and more suitable for patients with obesity and NAFLD, but the minimum exercise frequency required to improve health, especially in the long-term, is unknown. This proposed study aims to examine the effectiveness of long-term low-frequency HIIT for improving body adiposity and liver fat in centrally obese adults. The premise of this proposal is supported by recent findings that HIIT performed once a week could improve cardiorespiratory fitness, blood pressure, cardiac morphology, metabolic capacity, muscle power, and lean mass. This study will provide evidence for the benefits of long-term low-frequency HIIT with a follow-up period to assess its effectiveness, safety, adherence, and sustainability. We expect this intervention will enhance the practical suitability of HIIT in inactive obese adults and will provide evidence for low-frequency HIIT as a new exercise option in the management of obesity and NAFLD.

Enrollment: 160 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Cantonese, Mandarin or English speaking,
2. Aged 18-60,
3. Central obesity, defined as BMI ≥25 (obesity classification adopted by the Hong Kong Government) with waist circumference of ≥90 cm for men and ≥80 cm for women (abdominal obesity according to the International Diabetes Federation's Chinese ethnic-specific criterion),
4. Willing to initiate lifestyle modification but not pharmacologic or surgical means for treating obesity.

Exclusion criteria

1. ≥150 minutes moderate-intensity exercise or ≥75 minutes vigorous exercise weekly,
2. Regular HIIT (≥1 weekly) in the past six months,
3. Medical history of cardiovascular disease, chronic pulmonary or kidney disease, heart failure, cancer, and liver disease except for NAFLD,
4. Somatic conditions that limit exercise participation (e.g., limb loss),
5. Impaired mobility due to chronic diseases (e.g., chronic arthritis/osteoarthritis, neurological, musculoskeletal and autoimmune diseases),
6. Daily smoking habit,
7. Excess alcohol consumption (daily ≥30 g of alcohol for men and ≥20 g for women) in the past six months
8. Surgery, therapy or medication for obesity or weight loss in the past 6 months (e.g., gastric bypass, gastric band, sleeve gastrectomy, gastric reduction duodenal switch, and dietitian-prescribed dietary program).
9. During the study period, subjects identified with major physical changes that would considerably affect their body composition and weight (e.g., anorexia nervosa, bulimia nervosa, and prolonged gastrointestinal and digestive disorders) will be excluded.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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160 participants in 2 patient groups, including a placebo group

Usual Care Control

Placebo Comparator group

Description:

Subjects in the usual care control group will receive a health education program. This program includes 12-month twice-a-month sessions (70 minutes each session) for obesity-related health briefing, dietary caloric restriction advice, and lifestyle counseling/consultation. The class will be conducted in small group setting (4-8 participants each group). The same health information will be delivered to the subjects in the HIIT group throughout the 12-month intervention period. Subjects will be asked to attend \>70% of the classes.

Treatment:

Behavioral: Usual Care Control

High-intensity Interval Training Group

Experimental group

Description:

HIIT will be prescribed once weekly under the supervision of certified athletics coaches for 12 months. HIIT training will be performed in a small group setting (4-8 participants each group) in laboratories. In each session, subjects will run for four 4-minute intervals at 85%-95% of the peak heart rate (HRpeak) with a 3-minute active recovery at 50%-70% of the HRpeak between each interval. A 5-minute jog at an intensity of 70% of the HRpeak will be included for warm-up and cool-down before and after, respectively. Subjects will be asked to attend \>70% of the classes.

Treatment:

Behavioral: High-intensity Interval Training