Blood viscosity

Blood viscosity refers to the thickness and stickiness of blood. It is a measure of the resistance of blood to flow through the blood vessels. Blood viscosity is a crucial determinant of the friction against the vessel walls, affecting blood pressure and the work required by the heart to circulate blood. High blood viscosity can lead to an increased risk of heart attack, stroke, and other cardiovascular diseases.

Factors Influencing Blood Viscosity

Several factors can influence blood viscosity, including:

• Hematocrit: The proportion of red blood cells in the blood. Higher hematocrit levels increase blood viscosity.
• Plasma viscosity: The viscosity of the blood plasma, which can be affected by the concentration of proteins, such as fibrinogen and globulins.
• Temperature: Blood viscosity decreases with increasing temperature.
• Shear rate: The rate of deformation of the blood under shear stress. Blood exhibits non-Newtonian behavior, meaning its viscosity decreases with an increase in shear rate.

Clinical Significance

Blood viscosity is a critical factor in the circulatory system's function. Abnormal viscosity levels can lead to various health issues:

• High blood viscosity can impair blood flow, leading to increased blood pressure and strain on the heart. It is associated with a higher risk of cardiovascular diseases, such as coronary artery disease and peripheral artery disease.
• Low blood viscosity, although less common, can lead to excessive bleeding and difficulty in forming blood clots.

Measurement

Blood viscosity is measured using a viscometer or rheometer in a clinical laboratory setting. The measurement is typically conducted at a controlled temperature, often 37°C, which is the normal human body temperature.

Management

Management of abnormal blood viscosity focuses on addressing the underlying cause. This may include:

• Hydration: Increasing fluid intake can help lower blood viscosity.
• Medication: Drugs such as aspirin can reduce blood viscosity by inhibiting platelet aggregation. Other medications may target specific conditions contributing to altered viscosity.
• Lifestyle changes: Diet, exercise, and smoking cessation can also influence blood viscosity.

Conclusion

Blood viscosity is a vital parameter in understanding and managing cardiovascular health. Its regulation is essential for maintaining optimal blood flow and reducing the risk of vascular diseases.