Who will stay and who will go? A review of older adults' adherence to randomized controlled trials of exercise

This study examined exercise-adherence rates and their predictors across 21 randomized controlled trials (RCTs) involving older adults (age greater than or equal to 55 years). On average, participants completed 78% of their prescribed exercise bouts. Adherence tended to be greater in strength- and flexibility-exercise training programs (M = 87%) than in aerobic-exercise training programs (M = 75%). The best adherers were individuals who were fitter at baseline, had a history of a physically active lifestyle, were nonsmokers, and had higher exercise self-efficacy. Different variables predicted adherence (a) at different time points in a RCT, (b) to different types of exercise, and (c) to different aspects of the exercise prescription (i.e., frequency, intensity, and duration). The findings suggest that older adults might be more adherent to exercise prescriptions than younger adults are. There is also a need for more theory-based research to examine predictors of adherence to various aspects of the exercise prescription.