Effects of Progressive Intensity Exercise Training on Glycemic Control in Older Adults
Condition: PreDiabetes; Aging
MeSH terms: Prediabetic State
Study type: Interventional

Summary: 
      The purpose of this study is to compare the effects of moderate versus vigorous intensity
      exercise training on glycemic control in older adults. Glycemic control will be assessed
      using an oral glucose tolerance test and continuous glucose monitors. In addition, the
      investigaotrs will investigate whether engaging in an exercise training program elicits
      changes in sedentary behavior, non-exercise physical activity, sleep, and total daily energy
      expenditure.
    

Detailed description: 
      Approximately 25% of older adults have type 2 diabetes mellitus, and almost 50% of older
      adults have prediabetes. Identifying strategies to prevent the progression of diabetes in
      this older adult population is imperative. One strategy that has shown promise is lifestyle
      modification. As adults age they also increase sedentary behavior, decrease physical
      activity, and have increased occurrence of sleep problems. The combination of these lifestyle
      factors are likely responsible for the decreases in glycemic control with aging. The American
      Diabetes Association recommends that prediabetic adults, including older adults, increase
      structured aerobic exercise and incidental (non-exercise) physical activity while decreasing
      sedentary behavior. It is emphasized that structured exercise is the most important of these
      recommendations. However, initiating an exercise routine, may unintentionally affect time
      spent sitting, non-exercise physical activity, and other lifestyle behaviors like sleep.
      These changes may attenuate or enhance the effects of exercise on glycemic control. This
      study will compare the effects of moderate and high intensity exercise on glycemic control,
      and determine whether changes in non-exercise physical activity, sitting time, and sleep are
      associated with the observed changes. Because of the increasing prevalence of diabetes with
      age, identifying the optimal exercise prescription to preserve glycemic control in older
      adults has important clinical implications.
    

Intervention name(s): Moderate Intensity Exercise Training (MOD); Vigorous Intensity Exercise Training (VIG)
Intervention type(s): Behavioral; Behavioral
Intervention description(s): For the first 4 weeks, participant will be asked to complete 3 days of exercise/week at 50-65% heart rate maximum. Sessions will last between 30-40 minutes excluding the warm-up and cool down (5-10 minutes). After 4 weeks, the MOD group will be expected to match the exercise prescription. The exercise prescription for the MOD group for weeks 5-12 will be 4 days/week, 45 min/session completed at 60-65% heart rate maximum.; The exercise lead in period will be the same as the moderate intensity exercise training program. After 6 weeks, the VIG group will be expected to match the exercise prescription. The exercise prescription for the VIG for weeks 7-12 will be 4 days/week, 45 min/session completed at 80-85% heart rate maximum.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Prevention
Keywords: Exercise; Physical activity; Blood glucose; Sleep