Why does it seem that people starting in their sixties have so many major illnesses?

Natural aging: As we get older, our arteries are stiffer, and many develop high blood pressure. Cholesterol and plaque build up in arteries, leading to heart problems. These changes over years leads to health issues. Adult onset diabetes later in life, often associated with being over weight, A healthy lifestyle:not smoking, watching diet, keeping a normal weigh, exercise may reduce these illnesses