The HIIT Cognition Study

This pilot study is a randomized control trial to test the effects of a 14-week home-based virtual, interactive high intensity interval training (HIIT) exercise intervention on cardiometabolic and cognitive outcomes in sedentary youth with overweight/obesity during adolescence. All participants (N=24) will complete screening via phone to determine eligibility. Eligible participants will be randomized to receive a) 14 weeks of a home-based HIIT intervention delivered via iPad or b) 14 weeks of a stretching intervention (control group). Each participant will undergo an in-lab pre- and post-test visit, where they will complete a fasting blood draw, a fitness test, and various cognitive and mental health measures.

Rationale: Existing literature supports the premise that physical activity (PA) has beneficial effects on cognitive function in youth, but prior studies have limitations, such as cross-sectional designs with limited insights on the intensity or duration of PA or the biological underpinnings linking physical activity and mental health and cognitive function in adolescents. A limited number of studies (and none in the U.S.) have evaluated the effects of HIIT on cognitive processes in youth, particularly in youth with overweight/obesity whose age-related declines in PA puts them at increased risk for poor outcomes. This study is particularly timely during the current COVID-19 related public health crisis because our HIIT exercise intervention is time efficient, delivered remotely, and completed using space-efficient equipment in the home.

Intervention: Participants (youth ages 12-16 years with overweight/obesity) will be randomly assigned to complete a) 14 weeks of a home-based virtual, interactive HIIT intervention or b) 14 weeks of a stretching intervention (control group).

Objectives/Purpose: The overall goal is to improve cognitive and cardiometabolic outcomes in youth with overweight/obesity by implementing an at-home HIIT intervention. The aims of this study are: 1) to determine the feasibility, acceptability, and efficacy of HIIT in adolescents with overweight/obesity, 2) to examine the effectiveness of HIIT on cognitive and mental health outcomes, and 3) to examine the effectiveness of HIIT on cardiometabolic health.

Study Population: This study will consist of youth ages 12-16 years with overweight/obesity (BMI \>=85th percentile) who do not meet current PA guidelines.

Study Methodology: This pilot study is a randomized control trial to test the effects of a 14-week home-based virtual, interactive high intensity interval training (HIIT) exercise intervention on cardiometabolic and cognitive outcomes in sedentary youth with overweight/obesity during adolescence. All participants (N=24) will complete screening via phone to determine eligibility. Eligible participants will be randomized to receive a) 14 weeks of a home-based HIIT intervention delivered via iPad (HIIT group) or b) 14 weeks of a stretching intervention (control group).

Those randomized to the HIIT group will receive the intervention 3 times/week and will be given a pre-assembled stationary bicycle to use to complete each exercise session, an iPad to Zoom with the exercise trainers, and a Fitbit to assess real-time heart rate. Exercise trainers will provide encouragement and supervision for exercise prescription adherence and youth will select an age-appropriate music playlist from Spotify to enhance enjoyment throughout each session. Each exercise session consists of a 5-minute warm-up (10% HRmax), followed by a 20-minute HIIT protocol. The 20-minute HIIT protocol consists of seven bouts of 1-min high intensity exercise (90% HRmax) followed by 2-min of active recovery (10% HRmax). Participants will be encouraged to complete each exercise session with at least 24 hours of rest between each session.

Those randomized to the control group will perform a home-based program of the same stretches utilized in the exercise group. The stretching protocol consists of one set of 4 static stretching exercises held for 30 seconds and performed 3 days/week. As flexibility exercises are low-intensity, low-impact and low-volume, minimal caloric expenditure is expected to be incurred.

Study arms: Study participants will be randomly assigned to receive either the HIIT intervention (HIIT group) or receive the stretching intervention (control group).

Endpoints/Outcomes: The primary cognitive and mental health endpoints are: executive function, episodic memory, working memory, affect, mood, anxiety, stress, self-efficacy for PA, and PA enjoyment. The primary cardiometabolic endpoints are: glucose, insulin (to calculate Homeostatic Model Assessment for Insulin Resistance), IL-6, IL-1, TNF-a, and VEGF.

Statistical analyses: The populations for analyses include the full analytical dataset which consists of all randomized study participants.

Eligibility Criteria:
Inclusion Criteria:

1. Typically developing youth.
2. Overweight/obese (BMI \>= 85th percentile)
3. Does not meet current PA guidelines
4. Able and willing to complete HIIT exercise intervention.
5. Space for a stationary bike in the residence.

Exclusion Criteria:

1. Diagnoses of neurodevelopment or psychiatric disorders.
2. Diabetes, cardiovascular, pulmonary, or other significant medical problems.
3. Taking medications know to alter metabolism.
4. Allergy to metals.
5. Inability to participate in HIIT-based exercise or active involvement in sports/exercise programs.
6. Pregnancy.