Predictors of exercise frequency in breast cancer survivors in Taiwan

Abstract

To apply social cognitive theory to elucidate factors that motivate change in exercise frequency in breast cancer survivors during the six months after completing cancer treatment. Exercise is now a well-recognised quality-of-life intervention in breast cancer survivors. However, only regular exercise yields long-term benefits. Motivations for exercise have not been analysed in Taiwan patients with cancer. A prospective, longitudinal and repeated measures design was used. A convenience sample of 196 breast cancer survivors was recruited from hospitals in metropolitan areas of north and south Taiwan. Study participants were allowed to select their preferred exercised activities. Exercise behaviour and other factors were then recorded using various standardised instruments. Medical charts were also reviewed. Data were analysed by a linear mixed model and by hierarchical multiple regression equations. Exercise frequency significantly changed over time. Explained variance in exercise frequency change was modest. Baseline exercise frequency was the best significant predictor of exercise frequency during the six-month study. The study also identified possible age-related differences in the effect of social support on exercise. The effect of social support for exercise on exercise frequency was apparently larger in older subjects, especially those over 40 years old, than in younger subjects. Mental health, exercise barriers and exercise outcome expectancy significantly contributed to change in exercise frequency during the six-month study. The analytical results revealed several ways to increase exercise frequency in breast cancer survivors: (1) encourage exercise as early as possible; (2) improve health status and provide social support for exercise, especially in women aged 40 years or older; (3) reduce exercise barriers and promote mental health; (4) reinforce self-efficacy and positive expectations of exercise outcomes and (5) provide strategies for minimising fatigue in early stages of rehabilitation. Relevance to clinical practice. Social cognitive theory provides a useful framework for understanding the motivation to exercise in breast cancer survivors.