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Completed

NCT Number: NCT04887454

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

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.

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Key information

Conditions

Obesity Body Weight Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Metabolic Diseases Metabolic Syndrome Nutrition Disorders Nutritional and Metabolic Diseases Obesity, Abdominal Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

LKS Faculty of Medicine

Hong Kong

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Once-Weekly HIIT

Behavioral

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 HIIT

Behavioral

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.

Usual Care

Other

Participants in the usual care control group will receive health education delivered by research personnel. This program will consist of eight two-hour bi-weekly sessions covering major health issues relating to obesity including causes, prevalence, epidemiology, associated diseases, healthy diet, caloric restriction advice, physical activity, stress management, adequate sleep, as well as lifestyle counseling/consultation and goal-setting/record-keeping strategies for behavioral changes.

Primary outcomes

  1. Change in Body Fat

    Time frame: Baseline and 4 months

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

Secondary outcomes

  1. Change in Body Fat

    Time frame: Baseline and 8 months

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

  2. Change in Abdominal Visceral Fat

    Time frame: Baseline and 4 and 8 months

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

  3. Change in Abdominal Subcutaneous Fat

    Time frame: Baseline and 4 and 8 months

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

  4. Change in Body Mass Index

    Time frame: Baseline and 4 and 8 months

    Weight and height will be assessed using a calibrated electronic digital weighing scale and stadiometer respectively

  5. Change in Waist Circumference

    Time frame: Baseline and 4 and 8 months

    Waist circumference will be assessed using an inelastic measuring tape to the nearest 0.1cm on bare skin

  6. Change in Systolic Blood Pressure

    Time frame: Baseline and 4 and 8 months

    Resting systolic blood pressure will be assessed

  7. Change in Diastolic Blood Pressure

    Time frame: Baseline and 4 and 8 months

    Resting diastolic blood pressure will be assessed

  8. Change in Fasting Glucose

    Time frame: Baseline and 4 and 8 months

    Fasting glucose will be analyzed from venous blood by an accredited medical laboratory

  9. Change in Fasting Triglycerides

    Time frame: Baseline and 4 and 8 months

    Fasting triglycerides will be analyzed from venous blood by an accredited medical laboratory

  10. Change in Fasting Low Density Lipoprotein Cholesterol (LDL-C)

    Time frame: Baseline and 4 and 8 months

    Fasting LDL-C will be analyzed from venous blood by an accredited medical laboratory

  11. Change in Fasting High Density Lipoprotein Cholesterol (HDL-C)

    Time frame: Baseline and 4 and 8 months

    Fasting HDL-C will be analyzed from venous blood by an accredited medical laboratory

  12. Change in Fasting Total Cholesterol

    Time frame: Baseline and 4 and 8 months

    Fasting total cholesterol will be analyzed from venous blood by an accredited medical laboratory

  13. Change in Proportion of Metabolic Syndrome Diagnosis

    Time frame: Baseline and 4 and 8 months

    Metabolic syndrome diagnosis will be evaluated with waist circumference, triglycerides, HDL-C, blood pressure, and fasting glucose

  14. Number of Adverse Events

    Time frame: Baseline and 4 and 8 months

    Adverse events related or unrelated to training will be assessed

  15. Change in Organ Fat

    Time frame: Baseline and 4 and 8 months

    Organ fat will be assessed using magnetic resonance imaging (MRI)

  16. Change in SF-12 Physical Component Summary Score

    Time frame: Baseline and 4 and 8 months

    Physical health-related quality of life will be assessed using the Physical Component Summary Score of the 12-Item Short-Form Health Survey (SF-12)

  17. Change in SF-12 Mental Component Summary Score

    Time frame: Baseline and 4 and 8 months

    Mental health-related quality of life will be assessed using the Mental Component Summary Score of the 12-Item Short-Form Health Survey (SF-12)

  18. Change in HADS-D Score

    Time frame: Baseline and 4 and 8 months

    HADS-D score will be assessed using the Depression subscale of the Hospital Anxiety and Depression Scale (HADS-D)

  19. Change in PHQ-9 Score

    Time frame: Baseline and 4 and 8 months

    PHQ-9 score will be assessed using the Patient Health Questionnaire-9 (PHQ-9)

  20. Change in HADS-A Score

    Time frame: Baseline and 4 and 8 months

    HADS-A score will be assessed using the Anxiety subscale of the Hospital Anxiety and Depression Scale (HADS-A)

  21. Change in GAD-7 Score

    Time frame: Baseline and 4 and 8 months

    GAD-7 score will be assessed using the General Anxiety Disorder-7 (GAD-7) Questionnaire

Sponsors and collaborators

Lead sponsor

The University of Hong Kong

Other

Registry information

Important dates

Study start
2021
Primary completion
2024
Study completion
2024
First posted
May 14, 2021
Registry last updated
Mar 30, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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