What happen if the viscosity of the blood is high?
Increased viscosity increases the resistance to blood flow and thereby increases the work of the heart and impairs organ perfusion. Some patients with anemia have low hematocrits, and therefore reduced blood viscosities. Another important factor that influences blood viscosity is temperature.
What affects blood viscosity the most?
The two most important determinants of blood viscosity are the hematocrit and fibrinogen levels. In patients with hematocrits in the range of 47–53%, lowering of the hematocrit by phlebotomy to below 40% can increase cerebral blood flow by as much as 50%. Blood pressure is also important.
What is blood viscosity affected by?
Blood viscosity depends on several factors: hematocrit, plasma viscosity, the ability of RBCs to deform under flow, and RBC aggregation-disaggregation properties (Baskurt and Meiselman, 2003; Cokelet and Meiselman, 2007).
What causes increased blood viscosity?
Hyperviscosity can be caused by your blood cells changing shape or by an increase in serum proteins, red blood cells, white blood cells, or platelets. The reduced blood flow caused by hyperviscosity syndrome is a dangerous phenomenon and can have far-reaching effects on the whole body.
What happens when blood viscosity decreases?
The relationship between BP and viscosity is such that, given a constant systolic BP, if blood viscosity increases, then the total peripheral resistance (TPR) will necessarily increase, thereby reducing blood flow. Conversely, when viscosity decreases, blood flow and perfusion will increase.
What effect would you expect an increased blood viscosity to have on blood pressure?
According to this equation, a decrease in viscosity causes an increase in cardiac output and opposite this, an increase in viscosity causes a decrease in cardiac output. Therefore, the physiologic compensation of viscosity-related decreased blood flow rate will be an increase in pressure or vasodilation.
How does exercise affect blood flow?
Exercising muscles need more blood. And in response to regular exercise, they actually grow more blood vessels by expanding the network of capillaries. In turn, muscle cells boost levels of the enzymes that allow them to use oxygen to generate energy.
How does blood viscosity affect resistance?
Blood Viscosity The viscosity of blood is directly proportional to resistance and inversely proportional to flow; therefore, any condition that causes viscosity to increase will also increase resistance and decrease flow.
What are the symptoms of blood viscosity?
Symptoms of high blood viscosity include spontaneous bleeding from mucous membranes, visual disturbances due to retinopathy, and neurologic symptoms ranging from headache and vertigo to seizures and coma.
How does blood viscosity affect arterial pressure?
Although it is commonly accepted that sustained hyperviscosity can decrease perfusion and increase blood pressure, it should be noted that increased blood viscosity has two effects in the cardiovascular system: it may act to increase shear stress on the endothelium and increase NO release, promoting vasodilation as …
What happens to blood pressure if your blood is thick high viscosity?
How does blood viscosity affect peripheral resistance?
Peripheral resistance is determined by three factors: Autonomic activity: sympathetic activity constricts peripheral arteries. Pharmacologic agents: vasoconstrictor drugs increase resistance while vasodilator drugs decrease it. Blood viscosity: increased viscosity increases resistance.
How does blood viscosity affect cardiovascular disease survival?
The men in the highest viscosity group had the most cardiovascular events during the study period. The men in the lowest viscosity group—remember that they also had high blood pressure—had the longest event-free survival.
What are the causes of increased blood viscosity?
Increased blood viscosity can be caused by an increase in red cell mass or increased red cell deformity, increased plasma levels of fibrinogen and coagulation factors, and dehydration.
How do lipoproteins affect blood viscosity?
The effects of low-density lipoprotein and high-density lipoprotein on blood viscosity correlate with their association with risk of atherosclerosis in humans. Clin Sci. 1997;92:473-479.
How does blood loss affect viscosity and hematocrit?
The primary determinants of blood viscosity are highly affected by a woman’s monthly blood loss. The effect on hematocrit is obvious: the monthly loss of 1 to 3 oz of blood will decrease the volume of RBCs. The effect on RBC deformability may be less obvious.