The cardiovascular system depends on the health and function of the vasculature and circulating blood as well as the heart pump itself. Exercise benefits the vasculature and heart muscle as much as it improves skeletal muscle function. Cardiovascular exercise is among the most beneficial to one's health, emphasizing the importance of this omnipresent organ system.
Blood Vessels
Your body has two general classes of blood vessels: arteries and veins. Arranged much like the branches of a tree, the vascular network that arises from large arteries, deeply penetrating organ systems as capillary networks, ultimately emerges as a thickening, flaccid venous conglomerate. The vasculature is a complex organ system itself; its proper function depends on the health of multiple cell types, including endothelial cells. Vital to the health of the entire vascular structure, this thin layer of cells, bordering the muscular elements of the vessel from the fluid, regulates the hemodynamic workings of the blood.
Hematology
The health and fluidity of the blood is an important factor in cardiovascular health. According to a 2011 article from the journal "Free Radical Research," the speed of red blood cells depends on the diameter of the blood vessel and deformability of the cells. During exercise, the blood vessels in your skeletal muscles demand more oxygen to support their activity and your body sends more blood to these areas. The rate at which your RBCs transverse the microcirculation of your muscles, deliver oxygen, and flow back to the heart to replenish their oxygen determines how much work the muscles can perform. When you exercise intensely, you push the capabilities of your system, testing blood's ability to support the fast rates of muscle metabolism. Increased rates of blood flow can be attributed to increased vessel diameter and increased malleability of the RBCs. Regular exercise will keep your blood flow at appropriate speeds and prevent it from becoming static. Slow-moving blood, as sometimes occurs in the heart and deep veins, has a higher probability of coagulating and forming a clot in the circulation.
Endothelial Cells
An important cell type in cardiovascular physiology is the endothelial cell. At first glance, these cells appear to simply act as a physical barrier between the circulating blood and the muscular tissue of arteries. Research has continued to reveal, however, an active role of endothelial cells in vascular health. According to the 2011 article "Exercise-Induced Modulation of Endothelial Nitric Oxide Production," endothelial cells play an active role in regulating blood vessel dilation and constriction. Through various regulatory pathways, endothelial nitric oxide production will respond to changes in blood flow by altering vessel diameter. For example, with increasing shear stress within vessels, as may occur with high blood pressure or during exercise, endothelial cells detect the abnormality and send a nitric oxide chemical signal to dilate the arteries, which will promote healthy blood flow throughout the system.
Atherosclerosis
The importance of endothelial cells in cardiovascular health has been uncovered through the study of atherosclerosis, a common vascular disease in the U.S. This process of fat and plaque accumulation in major arteries has been attributed to damage to endothelial cells, which eventually lose contact with supportive tissues as debris builds up within the walls of the vasculature. As these cells lose support lines, they stop producing valuable nitric oxide, often leading to vasoconstriction and problems with blood flow. When this process affects blood vessels entering the heart, it is referred to as coronary artery disease. Exercise helps reverse atherosclerosis by decreasing blood levels of fat and removing plaque accumulations from major arteries.
Benefits
Regular exercise provides tremendous benefits to your health; improvements in heart function are among the most valuable of these benefits. Improvements in cardiopulmonary and metabolic function are often documented, as well as reductions in the risk of coronary artery disease, stroke, and even cancer.
References
- Free Radical Research: Nitric Oxide influences red blood cell velocity independently of changes in the vascular tone; Horn P, et.al; 2011
- "Current Pharmacology and Biotechnology"; Exercise-Induced Modulation of Endothelial Nitric Oxide Production; Gielen S, et.al; 2011
- "Korean Circulation Journal"; Exercise, Heart, and Health; Nam GB; March 2011
