What physiological change in older clients can lead to elevated systolic blood pressure?

The physiological change that leads to elevated systolic blood pressure in older clients is the loss of arterial elasticity. As individuals age, their arterial walls can become stiffer and less compliant due to various factors such as the accumulation of collagen and the decrease in elastin. This loss of elasticity means that the arteries are not able to expand as effectively to accommodate the pressure from the heart's contractions. As a result, when the heart pumps blood, the pressure in the arteries can increase, leading to elevated systolic blood pressure.

In contrast, a decrease in blood volume can generally lead to lower blood pressure, while an increase in calcium intake would not typically impact blood pressure directly in the context of arterial health. A decrease in cardiac output may also reduce blood pressure, as it refers to the total amount of blood being pumped by the heart. Therefore, the loss of arterial elasticity is a key factor in the phenomenon of increased systolic blood pressure seen in older adults.