Project Summary/Abstract Although breast cancer is the most frequently diagnosed cancer in the world, recently, the survival rate has greatly improved. With this improved survival rate, there is a growing population of obese, older adult breast cancer survivors facing unique challenges and late effects on brain health. Breast cancer survivors suffer cognitive impairments before, during, and post- treatment; more than one third experience persistent cognitive impairment lasting decades. Anxiety is the most common psychological symptom among cancer survivors, and frequently unrecognized and undertreated in health care settings. These survivors are also at increased risk of Alzheimer’s disease or dementia. There is unanimous consensus that physical activity and alcohol consumption are key modifiable behaviors to improve the physical and mental health of cancer survivors. Further, the American Cancer Society promotes increasing physical activity, and avoiding alcohol to manage treatment-related cognitive impairment. Although the benefits of physical activity for cancer survivors are well-established, the evidence is predominantly derived from guidelines-based, moderate-to-vigorous-intensity physical activity. However, survivors often do not meet guidelines for moderate-to-vigorous-intensity physical activity, do not adhere to physical activity interventions set at this intensity, and enjoy and prefer lighter-intensity activities. Much less is known about the effects of light-intensity physical activity on cognitive function and anxiety symptoms, and the 2018 United States Physical Activity Guidelines Advisory Committee Scientific Report identified the need to determine the role and contribution of light-intensity activity to diverse health outcomes as an overarching research need. Additionally, less is known about the effects of physical activity interventions on changes in alcohol consumption. Recent findings indicate physical activity may unintentionally increase alcohol consumption among cancer survivors. Increasing alcohol consumption places survivors at increased risk of recurrence, and may confound the positive effects of physical activity. Therefore, in the process of evaluating the effects of light-intensity physical activity on brain health outcomes among obese, older adult breast cancer survivors, the effects on alcohol consumption should be evaluated as well, to avoid unintended consequences. The light- intensity physical activity-breast cancer survivors (LIPA-BCS) trial addresses multiple knowledge gaps, with a primary and secondary focus on improving cognitive function and anxiety symptoms. The proposed work builds on this existing randomized controlled trial that randomizes obese, older adult breast cancer survivors 1-10 years post-breast cancer treatment, to either 15 weeks of light-intensity physical activity, or usual care. I will take advantage of this existing clinical trial to quantify and describe the effects on cognitive functio...