Heart and blood vessels become stiffer. The stiffer arteries are less able to expand when more blood is pumped through them. Blood pressure and often increase in elderly people and veins expand.
Differences between young and old hearts become apparent when the heart has to work hard and pump more blood—for example, during exercise or an illness. An older heart cannot speed (fast acceleration) up as quickly or pump as fast or as much blood as a younger heart. Older athletes are not able to perform as younger athletes.