Reduced antioxidant levels in PAD
November 9, 2012. An article published on September 24, 2012 in the Journal of Physiology reveals a protective role for antioxidants, particularly vitamin C, against the rise in blood pressure that occurs in the legs of individuals with peripheral arterial disease (PAD) during exercise. Peripheral artery disease is characterized by poor blood flow and pain in the lower extremities due to the presence of plaque (atherosclerosis).
Lawrence Sinoway and his colleagues at Penn State Hershey Heart and Vascular Institute compared the effects of exercise in subjects with and without PAD. They found an increase in blood pressure in the legs of PAD patients compared to those without the disease. Preadministration of high dose intravenous ascorbic acid reduced this effect in PAD patients by 50 percent. In another experiment in which subjects with and without PAD had their leg muscles electrically stimulated, increases in blood pressure were greater in those with PAD, indicating that the response came directly from the muscle, rather than from the brain.
“Past studies have shown that having low antioxidant levels and increased reactive oxygen species — chemical products that bind to body cells and cause damage — is related to more severe PAD,” commented lead author Matthew Muller, who is postdoctoral fellow in Dr Sinoway’s lab. “This study shows that blood pressure increases more with exercise in more severe PAD cases. By infusing the antioxidant vitamin C into the blood, we were able to lessen the increase in blood pressure during exercise.”
“This indicates that during normal, everyday activities such as walking, an impaired antioxidant system — as well as other factors — plays a role in the increased blood pressure response to exercise,” he added. “Therefore, supplementing the diet with antioxidants may help these patients, but more studies are needed to confirm this concept.”