Which of the following factors can lead to an increase in diastolic blood pressure?

Decreased physical activity can lead to an increase in diastolic blood pressure because physical activity plays a crucial role in maintaining cardiovascular health and regulating blood pressure. When individuals are less active, their heart may not condition itself as effectively to pump blood efficiently throughout the body. A sedentary lifestyle can lead to weight gain, increased arterial stiffness, and higher resistance in blood vessels, all of which contribute to elevated diastolic blood pressure.

In contrast, increased physical activity generally leads to better blood pressure control. Regular exercise helps improve heart function, promote weight management, and enhance vascular health, ultimately helping to lower both systolic and diastolic blood pressure.

The other options relate to factors that typically have beneficial effects on blood pressure or are neutral in relation to increasing diastolic pressure. Thus, decreased physical activity stands out as a direct contributor to elevated diastolic blood pressure due to its negative impact on overall cardiovascular fitness.