DNA Methylation and Cancer Prevention: Duration and Intensity of Exercise
Condition: DNA Methylation
Study type: Interventional

Summary: 
      Specific aim 1. Using a fully crossed 2 (intensity) X 2 (duration) design, the investigators
      will demonstrate a dose-response relationship between volume of aerobic exercise and changes
      in DNA methylation over four months among previously sedentary women.

      Specific aim 2. There are no published data on the extent to which positive effects of
      exercise on methylation might decay if exercise is not continued. The investigators will
      gather data on the natural history of methylation decay after training.
    

Detailed description: 
      Specific aim 1. Using a fully crossed 2 (intensity) X 2 (duration) design, the investigators
      will demonstrate a dose-response relationship between volume of aerobic exercise and changes
      in DNA methylation over four months among previously sedentary women.

        -  Hypothesis 1: The investigators predict that there will be an interaction between
           intensity and duration characterized by a dose-dependent response to total exercise
           volume, such that women will experience the greatest improvements in methylation at high
           intensity/high duration (16.4 kcal/kg/week) and the least improvements in methylation at
           low intensity/low duration (5.6 kcal/kg/week).

        -  Hypothesis 2: The investigators predict that there will be a main effect of exercise
           duration, such that women exercising for 40 minutes/session, 4 sessions per week will
           show more improvement in DNA methylation compared with women exercising for 20
           minutes/session, 4 sessions per week.

        -  Hypothesis 3: The investigators predict that there will be a main effect of exercise
           intensity, such that women exercising at 75% of VO2max will show more improvement in DNA
           methylation compared with women exercising at 55% of VO2max.

      Specific aim 2. There are no published data on the extent to which positive effects of
      exercise on methylation might decay if exercise is not continued. The investigators will
      gather data on the natural history of methylation decay after training.

      • Hypothesis 4: At six months following the end of supervised exercise, the investigators
      will assess the influence of the different levels of initial training and the passage of time
      on DNA methylation, covarying whether or not participants continued to exercise. It is
      predicted that the highest volume group will show the greatest persistence of positive
      changes in DNA methylation. Alternatively, it is possible that all four groups will return to
      baseline methylation levels of methylation, and there will be no difference in methylation at
      6 months following the end of supervised exercise.
    

Intervention name(s): Exercise
Intervention type(s): Behavioral
Intervention description(s): The investigators will measure changes in DNA methylation as a result of four different intervention groups, i.e, high/longer, low/longer, high/shorter, low/shorter.
Other intervention name(s): GEM
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Health Services Research
Keywords: epigenetics; cancer; exercise; intensity; duration