Dose-Response to Exercise in Women Aged 45-75 Years (DREW)
Condition: Cardiovascular Diseases; Hypertension; Postmenopausal; Overweight or Obese
MeSH terms: Hypertension; Cardiovascular Diseases; Overweight
Study type: Observational

Summary: 
      To investigate the effects of different amounts of exercise on both cardiorespiratory fitness
      and risk factors for cardiovascular disease in sedentary, overweight, mildly hypertensive,
      but healthy, postmenopausal women aged 45 to 75 years.
    

Detailed description: 
      BACKGROUND:

      The primary goal of the Dose-Response to Exercise in Women aged 45-75 Years (DREW) was to
      investigate the effects of different amounts of exercise on both cardiorespiratory fitness
      and risk factors for cardiovascular disease. Participants were sedentary, overweight or
      obese, postmenopausal women who had high normal blood pressure or Stage I hypertension, and
      thus are at moderately high risk for cardiovascular disease. A total of 464 women (about 35%
      were recruited from minority groups) were randomly assigned to a control group (N = 102) or
      to 1 of 3 exercise groups (N = 155 for the lowest exercise dose and 104 in the 8-kcal/kg
      group and 103 in the 12-kcal/kg exercise group). Women assigned to the exercise groups
      exercised for 6 months at energy expenditures of 4, 8, or 12 kcal ·kg-1 · week-1. These
      exercise doses represent the consensus public health recommendation for physical activity
      from recently published guidelines from the U.S. Public Health Service, American Heart
      Association, and American College of Sports Medicine (8 kcal ·kg-1 · week-1) and at doses 50%
      below (4 kcal ·kg-1 · week-1) and 50% above (12 kcal ·kg-1 · week-1) the consensus dose. All
      women exercised at 50% of V02 max. The exercise sessions took place in the exercise
      laboratory, with individual supervision of each session and strict control of frequency,
      duration, and intensity. This was provided thorough documentation of the exact amount of
      exercise completed. Primary outcome measures are VO2 max and resting systolic blood pressure.
      Other cardiovascular disease risk factors, psychosocial variables, health-related quality of
      life, body composition, and fat distribution are secondary outcomes. Other secondary analyses
      included a focus on the extent to which observed dose-response effects are modified by
      baseline levels of fitness, ethnicity, risk factors, or age. Assessments will take place at
      baseline and 6 months. The research provided information about (1) patterns of change in
      outcomes produced by each of several exercise doses, (2) whether performing exercise at less
      than the current consensus dose has any benefit, (3) whether performing more exercise than
      the consensus dose has greater (or proportionally greater) health benefits, and (4) the
      characteristics of sedentary women who are most likely to benefit from various exercise
      doses.

      DESIGN NARRATIVE:

      A total of 464 sedentary, postmenopausal women at moderate risk for cardiovascular disease
      was randomly assigned to receive exercise training at one of three doses (4, 8, or 12
      kcal/kg/wk) or no exercise for six months duration. The specific aims were be to determine:
      (a) if women in the exercise groups have increased aerobic power (VO2max) over the six months
      compared to the no exercise group; (b) if women in the exercise groups have a greater
      reduction in resting systolic blood pressure than those in the no exercise group; and, (c) if
      there will be a dose-response gradient across the three exercise groups for changes in
      aerobic power and systolic blood pressure. Secondary aims include evaluating the effects of
      exercise dose on fasting blood lipids and lipoproteins, glucose, insulin, anthropometry,
      self-reported quality of life, and cardiovascular risk as determined by a multiple logistic
      risk function. Covariates to be controlled included dietary intake, physical activity
      (outside of the exercise program), smoking, alcohol intake, sleep habits, medication use
      (including hormone replacement therapy), demographics, menstrual history, personal and family
      medical history.
    

Intervention name(s): Exercise
Intervention type(s): Behavioral
Intervention description(s): Compared the effect of 50%, 100%, and 150% of the NIH Consensus Development Panel recommended physical activity dose on fitness in women.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Postmenopausal women aged 45 to 75 years who are overweight
      
Biospecimen description: 
      whole blood
    
Keywords: Cardiovascular Diseases; Hypertension; Postmenopausal; Overweight or Obese; Women; Sedentary