Living with prostate cancer is a unique challenge faced by millions of men across the globe. Existing research has indicated many potential methods of attenuating prostate cancer progression and preserving patients' quality of life, but is lacking in definitive conclusions regarding the effectiveness of these methods in practice. This study seeks to further investigate the impact of post-diagnosis physical activity on biological indicators of health and self-reported quality of life in a cohort of men with prostate cancer in Sweden. Participants are randomized to either a walking intervention group, which encourages walking 10,000 steps per day for one year, or to a standard-or-care control group, and followed for 11 weeks.