The HIIT Cognition Study

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.