Which factor does NOT affect blood pressure?

Body temperature does not have a direct and significant effect on blood pressure. While body temperature can influence various physiological processes, it is not typically considered a primary factor in the regulation of blood pressure.

In contrast, factors such as the narrowing of the arteries, known as arteriosclerosis or atherosclerosis, directly affect blood flow and pressure. When arteries narrow, the resistance to blood flow increases, which can elevate blood pressure. Similarly, increased thickness of blood, or increased viscosity, places more strain on the heart and blood vessels, potentially raising blood pressure as well.

Body position can also significantly influence blood pressure readings. For example, blood pressure is generally lower when an individual is lying down compared to when they are standing up, due to changes in blood flow dynamics and gravity's effects.

Thus, while temperature can play minor roles in cardiovascular health, it does not have the same immediate and notable impact on blood pressure as the other factors listed.