Regular exercise increases exercise self-efficacy and health-related quality of life (HRQOL); however, the mechanisms are unknown. We examined the associations of exercise adherence and physiological improvements with changes in exercise self-efficacy and HRQOL.
Middle-aged adults (N = 202) were randomized to 12 months aerobic exercise (360 minutes/week) or control. Weight, waist circumference, percent body fat, cardiopulmonary fitness, HRQOL (SF-36), and exercise self-efficacy were assessed at baseline and 12 months. Adherence was measured in minutes/day from activity logs.
Exercise adherence was associated with reduced bodily pain, improved general health and vitality, and reduced role-emotional scores (Ptrend ≤ 0.05). Increased fitness was associated with improved physical functioning, bodily pain and general health scores (Ptrend ≤ 0.04). Reduced weight and percent body fat were associated with improved physical functioning, general health, and bodily pain scores (Ptrend < 0.05). Decreased waist circumference was associated with improved bodily pain and general health but with reduced role-emotional scores (Ptrend ≤ 0.05). High exercise adherence, increased cardiopulmonary fitness and reduced weight, waist circumference and percent body fat were associated with increased exercise self-efficacy (Ptrend < 0.02).
Monitoring adherence and tailoring exercise programs to induce changes in cardiopulmonary fitness and body composition may lead to greater improvements in HRQOL and self-efficacy that could promote exercise maintenance.
Imayama, Mason, Chiachi Wang, Xiao, Duggan, Ching-Yun Wang, and McTiernan are with the Dept of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA. Alfano is with the Office of Cancer Survivors, National Cancer Institute, Bethesda, MD. Campbell is with the Dept of Physical Therapy, University of British Columbia, Vancouver, British Columbia, Canada. Foster-Schubert is with the Dept of Medicine, University of Washington, Seattle, WA.