Any number of body functions, substances, and medical conditions can cause the walls of the blood vessels to narrow and constrict. This constriction, known as vasoconstriction, is a symptom of other underlying conditions and treatments. It can range from mild to severe, depending on its specific cause.
Arterial vasoconstriction is the body's natural blood saving system. The process works by stopping a person from hemorrhaging and preventing severe blood loss by restricting overall blood flow in a time of need, such as after sustaining an injury. It typically occurs in the large arteries of the body, though it can also cause the veins and small arterioles to shrink as well.
Regulation and maintenance of the body's arterial pressure is also managed by this process. During cardiac problems, hypoxic vasoconstriction can also occur in order to increase and restore oxygen levels. The process is also an alert system to warn the body, which helps it return to homeostasis during a period of irregular function.
Physically during this process, a patient's flesh will likely turn pale due to less blood being allowed to reach the skin. It will also be cooler to the touch, given that the radiation of heat is temporarily halted as well. In many mammals, this helps restore the balance of heat in the body, and prevent hypothermia by diverting stores of heat toward the animal's center. Dilation of pupils can also be a symptom.
Causes of blood vessel constriction can vary. Both internal forces and exterior variables may induce the response. Vasopressors, or vasoconstrictors, are different chemical compounds that can trigger the condition. These can be in the form of medications, such as ADHD treatment stimulants, amphetamines, caffeine, antihistamines, and decongestants. Other medications that can bring about the reaction may be administered to treat hypotension.
Body temperature can also cause the response. If a person is exposed to severe cold, cutaneous vasoconstriction can occur. Different nervous system processes, hormone circulation, and other body system functions may also encourage the blood vessels to compress.
Though this constriction is a symptom itself, it can also contribute to other health conditions if it continues for extended periods. The narrowing of the blood vessels can cause erectile dysfunction. Secondary hypertension, as well as higher blood pressure, may also be caused by it. In very ill patients, medical professionals may also administer counteractive medications to stop or reduce the process.