The cardiovascular system delivers nutrients and oxygen to all cells in the human body. your heart is the pump that drives blood flow throughout your body. there are specific factors that can affect blood flow through the cardiovascular system. out such factors. read the statements below and determine which are true about such factors. a high viscosity of blood causes an increased resistance in the blood vessels and leads to slow blood flow. a low blood ph decreases the rate of diffusion through the blood vessels and leads to slow blood flow. as people age, plaque builds up in the arteries increasing vessel resistance, which leads to disease. the factors that most directly affect blood flow are blood pressure, blood volume, resistance and activity level. as people age, blood pressure decreases leading to more cardiovascular disease.