Training Interventions and Genetics of Exercise Response (TIGER)
Condition: Exercise Response
Study type: Observational

Summary: 
      Obesity established in adolescence strongly predicts obesity for the remainder of adult life,
      and the consequences are potentially devastating, characterized by a lifelong burden of
      co-morbid conditions and depression. This study will provide an exposure to physical activity
      that is designed to teach and empower sedentary college age individuals to become physically
      active. The investigators will evaluate whether such exposure can result in lasting changes
      in exercise behavior and body composition. The study will also provide a better understanding
      of the genetic factors that influence persistence in an exercise program and that influence
      whole body response to exercise training. Altering the course of obesity in adolescence has
      the potential to reduce the adult prevalence of obesity and consequently attenuate the public
      health burden of overweight and obesity in the investigators population.
    

Detailed description: 
      Among the greatest public health concerns today is the rapid rise in obesity in the pediatric
      population, which now exceeds 18% in children (6-11 y) and 17% in adolescents (12-19 y),
      while obesity among young adults (20-39 y) approaches 30%. Though much has been learned
      regarding the regulation of body weight and the development of adiposity, the prevalence of
      obesity continues to rise, demonstrating that even today the factors that predict healthy
      weight maintenance remain poorly understood. In fact, the transition from overweight
      adolescent to obese adult is almost inevitable, with the probability of obesity in adulthood
      exceeding 50% among children >13 years of age whose BMI percentiles meet or exceed the 95th
      percentile for age and gender. But what if we could deter the expected transition from
      overweight adolescent to obese adult and intervene on a young person at a critical time when
      he/she is beginning to feel empowered by independence? This is the essence of the Training
      Interventions and Genetics of Exercise Response (TIGER) Study. The TIGER Study began in 2003
      with the goal of identifying genetic factors that influence physiologic response to exercise
      training, while introducing sedentary college age individuals to regular exercise. Subjects
      in the TIGER Study currently underwent 30 weeks (2 semesters) of exercise training, 3 days
      per week for 40 minutes at 65-85% of age-predicted maximum heart rate. More than 80% of
      subjects lost weight or maintained their weight within 2 kg, and only 18% of subjects gained
      more than 2 kg. We have identified preliminary associations between gene variation and
      exercise dropout in the first phase of the study, and in phase 2 of the TIGER study, we will
      build on these observations. We will focus on three primary areas of investigation: 1) formal
      evaluation of the TIGER Study intervention protocol to achieve long-term change in the
      participants; 2) investigation of gene expression patterns in skeletal muscle and
      subcutaneous adipose tissue as a strategy for identifying genes related to exercise response;
      and 3) investigation of the association between genetic variation and exercise adherence.
      Subjects will undergo 35 weeks of exercise training based on the established TIGER protocol,
      and subjects will be re-contacted 6, 12, and 24 months following completion of the study
      protocol and questioned regarding current exercise habits and body weight. In addition,
      genetic analysis of candidate genes related to exercise behavior and neural signaling will be
      undertaken in order to identify genetic factors that may influence exercise adherence.
      Finally, patterns of gene expression in subcutaneous adipose, skeletal muscle, and peripheral
      leukocytes will be analyzed at baseline and following exercise training in order to identify
      factors that influence physiologic change consequent to exercise training. Results from this
      study are designed to enlighten our current understanding of how and why individuals respond
      and/or persist in exercise, with the ultimate goal of formulating better and more efficacious
      interventions for obesity.
    

Intervention name(s): Aerobic Exercise Training; Cognitive Component
Intervention type(s): Behavioral; Other
Intervention description(s): 40 minutes, 3 times a week for 35 weeks.; Provide general information about health and fitness
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The target for phase 2 of the TIGER study is a student, age 18-30, who has not engaged in
        moderate physical activity more than 30 minutes per week for the previous 30 days and who
        is not actively limiting his/her caloric intake by dieting. It is planned to enroll a total
        of 3,200 subjects from student populations at the University of Houston (UH) and the
        University of Alabama at Birmingham (UAB) and representative of the race/ethnicity
        distribution of the respective campuses. Approximately 2,400 subjects will participate in
        the exercise protocol (600/yr for four years). A control group (200/yr for four years) will
        also be recruited that will not participate in the formal exercise for at least 35 weeks,
        but will be given the option of completing the formal exercise program after that time.
      
Biospecimen description: 
      Blood components and DNA
    
Keywords: Exercise; Activity; Adherence; Genetics