Exercise has lots of benefits for everyone, whether you are young or old, slender or large, able-bodied or living with a chronic illness or disability. Physical activity can reduce your risk of serious illness, including heart disease, stroke, diabetes and some forms of cancer, including lung cancer. Being active can help you stay active, by strengthening bones, improving flexibility and agility, reducing weight gain and improving sleep. Regular exercise is good for your head too. It can reduce feelings of anxiety and depression, improve attention and memory, and reduce the risk of dementia, including Alzheimer's disease.