Peripheral vascular resistance

Definition

Peripheral vascular resistance refers to the resistance that blood encounters as it flows through the peripheral blood vessels, primarily the arterioles. This resistance plays a crucial role in regulating blood flow and blood pressure throughout the body, especially during and after physical activity, influencing how effectively the cardiovascular system adapts to chronic exercise.

5 Must Know Facts For Your Next Test

1. Peripheral vascular resistance is primarily determined by the diameter of arterioles; smaller diameters result in higher resistance.
2. During chronic exercise training, there is typically a reduction in resting peripheral vascular resistance, enhancing blood flow to working muscles.
3. Increased blood flow due to decreased peripheral vascular resistance during exercise helps meet the metabolic demands of active tissues.
4. Hormones like norepinephrine can increase peripheral vascular resistance by causing vasoconstriction of blood vessels.
5. An imbalance in peripheral vascular resistance can lead to conditions like hypertension, which impacts overall cardiovascular health.

Review Questions

• How does peripheral vascular resistance change with chronic exercise training, and what physiological mechanisms are involved?
  • Chronic exercise training typically leads to a decrease in peripheral vascular resistance at rest due to adaptations such as increased endothelial function and vasodilatory capacity of blood vessels. These changes allow for improved blood flow to working muscles during exercise. Additionally, regular physical activity enhances the ability of arterioles to dilate, which directly reduces resistance and facilitates more efficient circulation.
• Discuss the relationship between peripheral vascular resistance and blood pressure regulation during physical activity.
  • Peripheral vascular resistance is a key factor in determining blood pressure levels. During physical activity, an increase in cardiac output occurs while peripheral vascular resistance decreases due to vasodilation of active muscle vessels. This balance allows for adequate oxygen delivery to muscles without significantly elevating blood pressure. If peripheral vascular resistance does not decrease appropriately, it can lead to elevated blood pressure, potentially causing cardiovascular strain.
• Evaluate how chronic changes in peripheral vascular resistance might influence long-term cardiovascular health outcomes.
  • Long-term adaptations that lower peripheral vascular resistance through regular exercise contribute positively to cardiovascular health by reducing the workload on the heart and lowering systemic blood pressure. This can decrease the risk of hypertension and associated complications like heart disease. Additionally, improved vascular function enhances overall circulation and nutrient delivery, which supports better recovery and performance in physical activities. Such adaptations are vital for maintaining cardiovascular efficiency as one ages.

Related terms

Blood Pressure:

The force exerted by circulating blood on the walls of blood vessels, which is influenced by cardiac output and peripheral vascular resistance.

Vasodilation:

The widening of blood vessels, which decreases peripheral vascular resistance and increases blood flow to tissues, often occurring in response to exercise.

Cardiac Output:

The volume of blood the heart pumps per minute, which is influenced by heart rate and stroke volume and works in conjunction with peripheral vascular resistance to regulate overall blood flow.