Optimal Frequency of High-Intensity Interval Training for Centrally Obese Adults

The University of Hong Kong315 enrolled

Overview

The aim of this study is to examine the therapeutic effectiveness of two different exercise frequencies of high-intensity interval training (HIIT; once versus thrice weekly, with matched weekly exercise volume) on improving cardiometabolic risk factors in centrally obese adults.

HIIT is an emerging, popular, promising, cost-effective, and time-efficient exercise modality for managing obesity. Although lower-frequency HIIT is favorable for intervention adherence, the optimal exercise frequency of HIIT for alleviating obesity is unknown. This study is a three-arm randomized controlled trial. Centrally obese adults will be randomly allocated to three groups: the usual care control, once and thrice-weekly HIIT groups. Led by research personnel, the usual care group will receive obesity-related health education. Led by athletic coaches, the HIIT intervention groups will receive 16 weeks of once or thrice weekly HIIT (with matched weekly exercise volume). Outcome measures of this study will be examined at baseline, 4 months (post-intervention), and 8 months (follow-up), by assessors blinded to group allocation.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

315

Conditions

Obesity

Interventions

Once-Weekly HIITBEHAVIORAL

Participants in this group will receive a 16-week intervention of HIIT once weekly supervised by certified athletic coaches. Participants will perform four 4-minute intervals at 85%-95% peak heart rate with a 3-minute active recovery between each 4-minute interval. Participants will repeat the 25-minute HIIT bout three times with 30-60 minutes break in between each 25-minute HIIT bout. Health information provided to the usual care control group will be made available to the participants in the HIIT groups.

Thrice-Weekly HIITBEHAVIORAL

Participants in this group will receive a 16-week intervention of HIIT thrice weekly supervised by certified athletic coaches. Participants will perform four 4-minute intervals at 85%-95% peak heart rate with a 3-minute active recovery between each 4-minute interval. Health information provided to the usual care control group will be made available to the participants in the HIIT groups.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Aged above 18 years * Ethnic Chinese * Overweight (BMI ≥23 for Asian) * Centrally obese according to IDF and NCEP with Asian-specific cut-off (waist circumference ≥90 cm for males; ≥80 cm for females) * Males and females Exclusion Criteria: * Medical and somatic conditions that prevent brisk walking * Chronic diseases affecting mobility and motor function (e.g., neurological disease, musculoskeletal disorder, spinal cord injury, autoimmune, arthritis, Parkinson's Disease) * Chronic diseases affecting cardiorespiratory and metabolic health (e.g., cancers, cardio-/cerebrovascular diseases, heart disease, diabetes mellitus, pneumonia, chronic pulmonary diseases, nephritis, nephrosis) * Signs of cardiac arrhythmia indicated by aberrant electrocardiography during incremental VO2max test * Regular moderate-to-vigorous intensity exercise (≥150 min weekly) in the past 3 months, as screened by a specially designed questionnaire * Daily smoking habit * Excess alcohol consumption (daily ≥30g for men, ≥20g for women) in the past six months * Claustrophobia * Surgery, therapy or medication for obesity or weight loss in the past six months (e.g., gastric bypass, gastric band, sleeve gastrectomy, gastric reduction duodenal switch, and dietitian-prescribed dietary program)

Locations (1)

LKS Faculty of Medicine

Hong Kong, Hong Kong

Outcomes

Primary Outcomes

Change in Body Fat

Total body fat mass will be assessed using dual-energy X-ray absorptiometry (DXA)

Time frame: Baseline and 4 months

Secondary Outcomes

Change in Body Fat

Total body fat mass will be assessed using dual-energy X-ray absorptiometry (DXA)

Time frame: Baseline and 8 months

Change in Abdominal Visceral Fat

Abdominal visceral fat will be assessed using magnetic resonance imaging (MRI)