Type 2 diabetes mellitus (adult-onset diabetes) is a common disease that interferes with the body's ability to store nutrients, resulting in high blood levels of sugar. Over time, high blood sugar levels can lead to complications such as blindness, kidney failure, and heart disease. Exercise helps to control blood sugar, lower blood pressure and cholesterol levels, and prevent weight gain. Physically fit men with type 2 diabetes apparently live longer than those who are less fit. It is not known, however, whether physically active women with type 2 diabetes suffer fewer heart attacks and strokes than women who are inactive.