Dose-Response to Exercise in Women Aged 45???75 yr (DREW): Design and Rationale

Abstract

Physical inactivity in postmenopausal women contributes to a rise in atherogenic risk factors associated with the metabolic syndrome. Although regular physical activity positively contributes to health, inactivity progressively increases with age. The Dose Response to Exercise in Women aged 45-75 yr (DREW) study is designed to investigate the effect of different amounts of exercise training on cardiorespiratory fitness and risk factors for cardiovascular disease (CVD) in postmenopausal women at moderately increased risk of CVD. Methods: DREW will recruit 450 sedentary, healthy, postmenopausal women with a body mass index of 25-40 kg•m Ϫ2 , resting systolic blood pressure (BP) of 120-159 mm Hg, and a resting diastolic BP of Յ 99 mm Hg. Laboratory and self-report measures completed at baseline and 6 months include maximal oxygen consumption (V O 2max), resting BP, anthropometry, dietary habits, physical activity history, medication use, menstrual history, personal and family medical history, and fasting HDL cholesterol, LDL cholesterol, triglycerides, and glucose. Eligible participants are randomly assigned to a nonexercise group or one of three exercise groups. Participants exercise 3 to 4ϫ wk Ϫ1 at a heart rate equivalent to 50% of V O 2max expending 4, 8, or 12 kcal•kg Ϫ1 •wk Ϫ1 , depending on group assignment. This study will allow quantification of possible dose-response relations (50%, 100%, and 150% of the consensus physical activity recommendation) between exercise training and study outcomes. Conclusion: DREW can make important contributions to our understanding of the effects of physical activity in postmenopausal women and help refine public health and clinical recommendations for this group.

Effects of Different Doses of Physical Activity on Cardiorespiratory Fitness Among Sedentary, Overweight or Obese Postmenopausal Women With Elevated Blood Pressure

“…18 In brief, the study was a randomized, dose-response exercise trial with a no-exercise control group and 3 exercise groups with incrementally higher doses of energy expenditure. The research protocol was reviewed and approved annually by The Cooper Institute's institutional review board, and written informed consent was obtained from all participants prior to their joining the study.…”

“…Details of these calculations are presented in the DREW design and methods report. 18 A major objective of DREW was to evaluate exercise levels 50% below and 50% above the current public health recommendations to test whether the lower dose provides any benefit and whether the higher dose provides proportionally more benefit than the standard exercise levels of 8 kcal/kg per week. Thus, women were assigned to either a nonexercise control group or to groups that expended 4, 8, or 12 kcal/kg per week.…”

Heart Rate Variability and Exercise in Aging Women

“…9,24 Briefly, the DREW study was a randomized, dose-response exercise training trial complying with the Declaration of Helsinki comparing a nonexercise control group with three groups exercising at incremental doses (50%, 100%, and 150%) of the minimal NIH Consensus Development Panel's recommendation for energy expenditure. 10 The Cooper Institute and Pennington Biomedical Research Center's institutional review boards reviewed DREW annually.…”

Physical Activity and Weight Management Across the Lifespan

“…Other randomized controlled trials are currently underway to examine physical activity prospectively in other groups. For example, the DREW trial is examining the dose-response relationship to exercise in postmenopausal women (87). As seen in the study by Donnelly and colleagues, college women on average may need more physical activity than do college men to prevent weight gain.…”