Effects of High-Intensity Interval Training Exercise in Adolescents With Hepatosteatosis

The study investigators want to learn more about the effect of a type of exercise on non-alcoholic fatty liver disease (NAFLD), and on markers of health (for example, liver, heart, and overall health) and how the body uses energy in teenagers. The exercise we are studying is called high-intensity interval training, or HIIT. Some participants in this study will receive a 4-week exercise program, and the others will not.

Inclusion criteria

Initial Enrollment

• Ages 13-18 years (inclusive) for both sexes
• Any ethnic/racial background
• English speaking competence
• Teenagers ages 13-15 weighing more than 145 pounds OR teenagers ages 16-18 weighing more than 170 pounds
• Low risk to participate in an exercise program as determined by "The Physical Activity Readiness Questionnaire for Everyone"
• Late stages of puberty (i.e., Tanner stage IV or V) based on Tanner Staging.

Inclusion criteria

Control or Exercise Group

• Presence of Non-Alcoholic Fatty Liver Disease (NAFLD) as determined by FibroScan Controlled Attenuated Parameter (CAP) score
• Confirmed lack of diabetes as determined by Oral Glucose Tolerance Test (OGTT)
• Confirmed eligibility per medical history

Exclusion criteria

• Pre-pubertal or early stages of puberty
• Pregnancy
• Confirmed lack of NAFLD in the past 6 months via biopsy or MRI
• Presence of an implantable medical device or metal objects in the body (a contraindication for FibroScan and/or MRI)
• High-risk to participate in an exercise program as determined by "The Physical Activity Readiness Questionnaire for Everyone"
• Unable to cooperate with study procedures and tests including genetic or physical conditions impacting mobility over the past year
• Having known chronic illnesses/disorders that may independently affect study outcome measures: type 1 diabetes mellitus, type 2 diabetes, neurologic (e.g., epilepsy), developmental (developmental delay, autism spectrum disorder), endocrine (Cushing's, growth hormone deficiency), hepatic (other than NAFLD), autoimmune, cardiac and renal disorders
• Current history of poorly-controlled asthma.
• Taking any of the following medications that can affect study outcome at the time of enrollment: insulin, metformin, or any other anti-diabetics, antipsychotics, oral steroids, and anabolic drugs (growth hormone replacement therapy, testosterone, and oxandrolone).
• Adolescents who have a history of claustrophobia.
• Adolescents who need sedation in order to complete MRI.
• Adolescents determined ineligible by the study investigator or delegated staff.