HIIT vs. MICT Training Study

Physiological and Molecular Effects of High-intensity Interval Training (HIIT) vs. Moderate-intensity Continuous Training (MICT)

The purpose of this study is to compare the impact of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on human health outcomes in healthy sedentary subjects, over 12 weeks of exercise training.

The investigators will compare several health parameters, such as changes in multiomics profile, cardiorespiratory fitness, muscle strength, and body composition, before and after 12-week interventions of either HIIT or MICT.

Study Overview

• Status: Active, not recruiting
• Conditions: Sedentary; Lifestyle
• Intervention / Treatment: Other: Exercise intervention

• Study Type: Interventional
• Enrollment (Estimated): 135
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Stanford, California, United States, 94305-2200
      • Stanford University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Be 18-65 years of age
• Not be pregnant or lactating in the last 12 months, or planning to become pregnant for the next 4 months. A pregnancy test will be performed on the day of DXA scan in women of child-bearing potential. Not be post-partum during the last 12 months.
• Be generally healthy (a list of medical conditions and/or medication that will exclude participants is listed in the section below)
• Body mass index (BMI) > 18 to < 40 kg/m2
• Sedentary in the past year, defined as regular (structured) endurance exercise (e.g., brisk walking, jogging, running, cycling, elliptical, or swimming activity that results in feelings of increased heart rate, rapid breathing, and/or sweating) or resistance training (resulting in muscular fatigue), no more than 1 hour per week.

Persons bicycling as a mode of transportation to and from work >1 day/week etc. will not be considered sedentary.

Leisure walkers are included unless they meet the heart rate, breathing, and sweating criteria noted above.

Exclusion Criteria:

• Exclusion criteria are confirmed by either self-report (i.e., medical and medication histories reviewed by a clinician), screening tests performed by the study team, and/or clinician judgment as specified for each criterion.

A person may not participate in this study if any of the following applies to them:

• Diabetes (self-report and screening tests), which includes: i) treatment with any hypoglycemic agents (self-report, even for non-diabetic reasons) or ii) fasting glucose >125 or A1c >6.4 (screening test).
• Abnormal bleeding or coagulopathy (self-report): history of a bleeding disorder or clotting abnormality.
• Thyroid disease (screening test):

Thyroid Stimulating Hormone (TSH) value outside of the normal range for the laboratory. Individuals with hypothyroidism may be referred to their primary care provider (PCP) for evaluation and retested; any medication change must be stable for more than 3 months prior to retesting.

Individuals with hyperthyroidism are excluded, including those with normal TSH on pharmacologic treatment.

• Clinical diagnosis of Chronic Obstructive Pulmonary Disease (COPD) and/or pulmonary hypertension.
• Metabolic bone disease (self-report): i) history of non-traumatic fracture from a standing height or less and/or ii) current pharmacologic treatment for low bone mass or osteoporosis, other than calcium, vitamin D, or estrogen.
• Estrogens, progestins (self-report): supplemental, replacement or therapeutic use of estrogens or progestins within the last 6 months, other than birth control or to control menopausal symptoms.
• Elevated blood pressure readings (screening test): i) age < 60 years: any history of hypertension; ii) age > 60 years: resting blood pressure reading higher than 150/90 mmHg.

• Cardiovascular diseases (self-report, screening tests, and clinician judgment):

  i) Congestive heart failure, pericardial effusion, coronary artery disease, mild valvular heart disease, congenital heart disease, significant arrhythmia(at rest or with exercise), stroke, or symptomatic peripheral artery disease (self-report, screening test) ii) Positive stress induced wall motion abnormalities.

• Unexplained syncope.
• Abnormal blood lipid profile (screening test): either fasting triglycerides >500 mg/dLand/or LDL cholesterol (LDL-C) >190mg/dL.
• History of cancer treatment (other than non-melanoma skin cancer) and not "cancer-free" for at least 2 years. Anti-hormonal therapy (e.g., for breast or prostate cancer) within the last 6 months.
• Chronic infection: i) infections requiring chronic antibiotic or anti-viral treatment; ii) Human Immunodeficiency Virus; iii) individuals successfully treated for hepatitis C and virologically negative for at least 6 months are not excluded.
• Liver enzyme tests (alanine transaminase, aspartate transaminase) (screening test) >2 times the laboratory upper limit of normal.
• Chronic renal insufficiency (screening test): estimated glomerular filtration rate <60 mL/min/1.73 m2 from serum creatinine (mg/dL) by the Chronic Kidney Disease Epidemiology Collaboration equation
• Hematocrit (screening) >3 points outside of the local normal laboratory ranges for women and men
• Whole blood donation in the last 3 months or plans for blood donation during the entire protocol period. Platelet or plasma donation in the last week or plans for platelet or plasma donation during the entire protocol period
• Individuals receiving any active treatment for autoimmune disorders (including monoclonal antibodies) within the last 6 months.
• Alcohol consumption (self-report): i) more than 7 drinks per week for women and more than 14 drinks per week for men; ii) history of binge drinking.
• Consume of tobacco, e-cigarette, nicotine products, and/or marijuana more than 3 days a week.

Shift workers: night shift work in the last 6 months or planning night shift work during the study period.

• Hospitalization for any psychiatric condition within one year (self-report).
• Weight change (intentional or not) over the last 6 months of >5% of body weight or plan to lose or gain weight during the study.
• Inflammatory conditions including rheumatoid arthritis, inflammatory bowel disease, connective tissue disease including lupus, systemic lupus.
• Any musculoskeletal or ligamentous injury, amputation or congenital neurological defect that, in the opinion of the team clinician, would negatively impact or mitigate participation in and completion of the protocol.
• Any other cardiovascular, pulmonary, orthopedic, neurologic, psychiatric or other conditions that, in the opinion of the team clinician, would preclude participation and successful completion of the protocol. Any other blood tests value outside of normal range if that indicates a condition that might preclude participation in the study.
• Mental incapacity and/or cognitive impairment on the part of the participant that would inhibit adequate understanding of or cooperation with the study protocol.

EXCLUSIONS FOR MEDICATION USE:

Use of any new drug in the last 3 months or dose change for any drug in the last within 3 months

Participants will be excluded if they are taking any of the medication listed below:

Anticoagulants Antiarrhythmics Antiplatelet drugs (other than aspirin <100 mg/day) Beta blockers Lipid-lowering medications Chronic use of medium- or long-acting sedatives and hypnotics (short-acting non-benzodiazepine sedative-hypnotics are allowed) Two or more drugs for depression Mood stabilizers Antiepileptic drugs Stimulants, Attention-Deficit/Hyperactivity Disorder (ADHD) drugs Anti-psychotic drugs Muscle relaxants Chronic oral steroids Burst/taper oral steroids more than once in the last 12 months B2-agonists, allowed if on stable dose at least 3 months 5-alpha reductase inhibitors Daily phosphodiesterase type 5 inhibitor use Androgenic anabolic steroids, anti-estrogens, anti-androgens Growth hormone, insulin like growth factor-I, growth hormone releasing hormone Any drugs used to treat diabetes mellitus or to lower blood glucose Any drugs used specifically to induce weight loss Any drugs used specifically to induce muscle growth/hypertrophy or augment exercise-induced muscle hypertrophy Narcotics and narcotic receptor agonists Regular use of non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen more than 3 days a week Anti-malarials High-potency topical steroids Continuous use of antibiotics or other anti-infectives Monoclonal antibodies Any other medications that, in the opinion of local clinicians, would negatively impact or mitigate full participation and completion.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control group
Experimental: HIIT group; Participants randomized in this group will be assigned to 12 weeks high intensity interval training.	Other: Exercise intervention; 12 weeks of exercise training, 3 times per week, ~1h long
Experimental: MICT group; Participants randomized in this group will be assigned to 12 weeks of moderate-intensity continuous training.	Other: Exercise intervention; 12 weeks of exercise training, 3 times per week, ~1h long

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cardiopulmonary Exercise Testing	Change in VO2 max after training, measured during cardiopulmonary exercise testing	Baseline; 12 weeks
Clinical markers	Changes in measured lipids in mg/dL including total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides	Baseline; 12 weeks
Transcriptome after 12-week intervention	Change in mRNA-based expression measured in biospecimens after 12 weeks of training	Baseline; 12 weeks
Proteome after 12-week intervention	Change in protein measured in biospecimens after 12 weeks of training	Baseline; 12 weeks
Metabolome after 12-week intervention	Change in metabolites measured in biospecimens after 12 weeks of training	Baseline; 12 weeks
Lipidome after 12-week intervention	Change in lipids measured in biospecimens after 12 weeks of training	Baseline; 12 weeks
Epigenome after 12-week intervention	Change in epigenome measured in biospecimens after 12 weeks of training	Baseline; 12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Transcriptome after acute exercise	Change in mRNA-based expression measured in biospecimens after acute exercise tests	Baseline; 12 weeks
Proteome after acute exercise	Change in protein measured in biospecimens after acute exercise tests	Baseline; 12 weeks
Metabolome after acute exercise	Change in metabolites measured in biospecimens after acute exercise tests	Baseline; 12 weeks
Lipidome after acute exercise	Change in lipids measured in biospecimens after acute exercise tests	Baseline; 12 weeks
Epigenome after acute exercise	Change in epigenome measured in biospecimens after acute exercise tests	Baseline; 12 weeks
Lean muscle mass	Change in lean muscle mass in kg measured by dual-energy x-ray absorptiometry	Baseline; 12 weeks
Fat mass	Change in fat mass in kg measured by dual-energy x-ray absorptiometry	Baseline; 12 weeks
Leg strength	Change in leg strength measured by Biodex	Baseline; 12 weeks
Hand grip strength	Change in hand grip strength measured by Biodex	Baseline; 12 weeks
Resting heart rate	Change in resting heart rate measured by wearable devices	Baseline; 12 weeks
Metagenome profile	Change in metagenome profile from stool microbiome kit	Baseline; 12 weeks
Blood glucose	Change in blood glucose in mg/dl profile measured with continuous glucose monitor	Baseline; 12 weeks
Left ventricle (LV) mass	Change in left ventricle mass measured by echocardiogram	Baseline; 12 weeks
LV diastolic volume	Change in LV diastolic volume measured by echocardiogram	Baseline; 12 weeks
Ejection fraction	Change in ejection fraction measured by echocardiogram	Baseline; 12 weeks
Exercise Motivation	Change in exercise motivation level measured by motivation for physical activity (RM 4-FM) questionnaire. RM 4-FM scores four different dimensions of motivation, each on a 0-7 point composite scale, with higher scores indicating stronger motivation.	Baseline; 12 weeks
Exercise Self-Efficacy	Change in exercise self-efficacy measured by Exercise Self Efficacy questionnaire, , a 9-item scale providing a 9-28 point composite score, with higher scores indicating higher self-efficacy for exercise.	Baseline; 12 weeks
Depression	Change in depression presence and/or severity measured by Patient Health Questionnaire-8, an 8-item scale providing a 0-24 point composite score, with higher scores indicating greater severity.	Baseline; Week 4, 8, 12
Generalized Anxiety	Change in anxiety presence and/or severity measured by Generalized Anxiety Disorder-7 , a 7-item scale providing a 0-21 point composite score, with higher scores indicating greater anxiety.	Baseline; Week 4, 8, 12
Perceived Stress	Change in perceived stress measured by Perceived Stress Scale-10, a 10-item scale providing a 0-40 point composite score, with higher scores indicating greater perceived stress.	Baseline; Week 4, 8, 12

Collaborators and Investigators

• Sponsor: Stanford University

Study record dates

Study Major Dates

• Study Start (Actual): January 10, 2023
• Primary Completion (Actual): August 11, 2025
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: July 19, 2022
• First Submitted That Met QC Criteria: August 22, 2022
• First Posted (Actual): August 24, 2022

Study Record Updates

• Last Update Posted (Actual): November 28, 2025
• Last Update Submitted That Met QC Criteria: November 22, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Behavior; Sedentary Behavior
• Other Study ID Numbers: 64208

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No