Vasodilation: Facts, Resources, and Treatments

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What is vasodilation?

Why does the skin flush during exercise? Or perhaps when he or she is embarrassed or enjoying a glass of wine? Without the person knowing any better, his or her body is in the midst of a process called vasodilation. Vasodilation is the widening or dilation of the blood vessels in direct response to the smooth muscle cells relaxing within the vessel walls. The word vasodilation stems from the Latin words “vasa,” meaning vessel, and “dilate,” which means to widen.

While the process takes place in some of the smallest places of the body, the veins and capillaries, this crucial physiological process has an impact on a growing health concern around the world – high blood pressure. It is important to control high blood pressure because of the undue stress it can otherwise have on the heart. High blood pressure increases one’s risk of having a heart attack or stroke, and can also put the individual at risk for other health problems, such as kidney failure.

How Vasodilation and Vasoconstriction Work

On the opposite of the spectrum, but still crucial to the regulation of blood pressure and body temperature is vasoconstriction. Both vasodilation and vasoconstriction work on the theory that the blood carries heat. As such, wherever blood flows, the heat does as well. When blood pressure or body temperature is high, vasodilation is implemented, aiding the body in the cooling process. The opening of the blood vessels increases the flow of blood, enabling the heat to travel to the surface of the body and escape into the atmosphere. The extra heat moving to the skin’s surface causes the skin to flush with redness and deepen in color.

In colder weather, the body needs more heat, requiring vasoconstriction to occur. Instead of increasing the blood flow like vasodilation, vasoconstriction refers to the narrowing of the blood vessels, raising the blood pressure and increasing body temperature. This increase is caused by friction from the blood passing through the internal walls of the vessels. The result is decreased blood flow to the surface of the skin, and less heat being released from the body.

Vasodilation directly affects the relationship between the average blood pressure in the volume of blood being pumped by the heat and the total peripheral resistance, or TPR. TPR is the total amount of the resistance of all peripheral vasculature in the systemic circulation. An increase in cardiac output or PR can cause the arterial pressure to rise. Vasodilation helps to decrease the TPR and blood pressure by relaxing the smooth muscle cells in the large arteries and arterioles.

Vasodilator Prescription Drugs

Though vasodilation and vasoconstriction are natural processes of the body, the prominence of heart disease has created a demand for pharmaceutical drugs to assist those who have deficiencies in either of the two functions. This group of drugs, called vasodilators, help the blood vessel walls to widen and relax, allowing the blood to flow more freely and reduce blood pressure. Vasodilators are used to treat a variety of heart-related conditions including hypertension, heart failure, and angina.

Examples of vasodilator drugs used for “afterload reduction” in a failing heart to ease the work of “pumping” are nitrates such as nitroprusside and nitroglycerine.

There are several different types of vasodilator drugs, each with a unique function. Arterial dilators are typically prescribed for high blood pressure and heart failure, but not angina. Venous dilators are used for treating the veins, and are used to treat angina, and sometimes heart failure. Mixed dilator drugs treat both the veins and the arteries, combating several key areas. The majority of the vasodilator prescriptions fall into this category.

Resources about Vasodilation

Dr. Bindon information about Vasodilation along with other Human Adaptability facts.

Barry W. Allen and Claude A. Piantadosi paper about “How do red blood cells cause hypoxic vasodilation? The SNO-hemoglobin paradigm”.

Britannica’s definition of Vasodilation.

Clinical Trials studies about Effects of Intensive Long-Term Vasodilation in Hypertensive Patients With Microvascular Angina Pectoris

PDF about the acute effects of vasodilator drugs in human beings have been usually evaluated through changes in arterial blood pressure and heart rate.

Resource by AnnaBelle

Annalise Kaylor is a freelance writer, editor, and consultant specializing in search engine optimized content for the web. As a writer, her work has appeared across the United States in print ads for Whirlpool, Maytag, Home Depot, and Lowe's, among others. As a consultant, she has worked primarily in the education sector, helping universities increase their web visibility and construct and implement social media strategy. Annalise is an avid reader, knitter, organic gardener and baker, as well as the author of the popular baking blog, Knead To Be Loaved. Annalise enjoys fly fishing, camping, and hiking.

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