After chemotherapy, older breast cancer survivors experience a faster decline in brain function. This can make it harder to enjoy life, stay social, and maintain independence. Chemotherapy can lead to poorer lifestyle habits, like unhealthy eating, less exercise, high stress, and poor sleep. Chemotherapy can also affect important health markers like blood sugar and cholesterol. Over time, these changes can damage blood vessels, which might lead to heart and brain issues. The investigators do not fully understand why brain function declines faster after chemotherapy, especially in older survivors, because there are many factors involved. In this study, the investigators will look at how lifestyle habits (like diet, exercise, stress and sleep), health markers (like blood sugar and cholesterol), and blood vessel health (like how well blood flows and how stiff the blood vessels are) affect brain function in older breast cancer survivors. The investigators will include 152 females aged 60-85 years, who finished chemotherapy for early-stage breast cancer at least 1 year ago. The investigators will use special tests to check different parts of brain function, like language, memory, and attention, as well as brain blood vessel health. This will help to understand which factors might speed up or slow down memory and thinking problems. Since many Canadian breast cancer survivors experience faster decline in brain function after chemotherapy, this study aims to find out what might make it worse. The results could help to create better and more personalized treatment plans for older breast cancer survivors that protect brain health and reduce problems with brain function in the future.