As if creaking joints and hardening of the arteries weren’t bad enough, a research team from the University of Delaware and the Christiana Care Health System in Newark has now confirmed that even our veins stiffen as we age.
“When you are young, your veins are nice and elastic–like rubber bands,” William Farquhar, a cardiovascular physiologist in UD’s College of Health Sciences, said. “But as you grow older, we’ve found that your veins become more like lead pipes.”
And that physiological change may be an important factor in the development of high blood pressure, or hypertension, which currently affects an estimated 65 million Americans, most of them older adults, according to Farquhar.
The study, which was conducted over the past two years, was led by Farquhar and Colin Young from the University of Delaware and Michael Stillabower and Angela Disabatino at Christiana Care Health System. The results are published in the November issue of the Journal of Applied Physiology.
Young recently completed his bachelor’s and master’s degrees at UD, with Farquhar as his adviser, and is now pursuing a doctorate in physiology and pharmacology at the University of Missouri. Stillabower is a cardiologist and director of cardiovascular research at Christiana Care Health System, as well as a clinical associate professor of medicine at Jefferson Medical College in Philadelphia. DiSabatino is the nurse manager at Christiana Care’s cardiovascular research office.
While the arterial side of the human circulatory system has been studied extensively, Farquhar said much less research has been conducted on the venous system. Yet the veins contain approximately 70 percent of your body’s total blood volume when you are at rest, and the flexibility of these blood vessels is a major factor in how much blood gets returned to your heart during the vital fluid’s journey through your circulatory system.
Every minute, the steady beating of that amazing living pump–your heart–sends about five quarts of blood through the 60,000-mile network of arteries, capillaries and veins in your body. The muscular arteries carry blood away from the heart and out to your organs and limbs. Microscopic capillaries connect the arteries to the veins. The veins then transport the blood back to the heart.
The veins are equipped with valves to prevent any backflow of blood caused by gravity as blood is returned to the heart from the lower extremities. The walls of the veins are made of collagen and elastin, two proteins that give the tube-like blood vessels flexibility and help them to maintain your blood pressure.
To determine if there are age-related differences in how our veins work, the research team recruited 24 people for their study–12 healthy young adults between the ages of 18 and 30, and 12 healthy older adults between 60 and 70 years old. Each individual underwent medical screening at Christiana Hospital, which included a lipid profile, blood pressure monitoring, electrocardiogram and several other tests to ensure overall good health.
Then each participant was involved in a series of research trials at UD’s Human Performance Lab on the Newark campus. While each subject lay resting on a gurney, various gauges, connected to computers, were placed on their arms and legs. An arterial cuff was attached to an upper arm to monitor blood pressure, and venous cuffs were placed around the upper thigh and upper arm to measure the blood flow to the limbs.
As the cuffs were inflated over an eight-minute period, and then slowly deflated to let blood escape from the limbs, the blood volume was measured, recorded, and graphed. The consistently lower blood volume under pressure pointed to the less springy veins of the older participants.
Source: University Of Delaware. Oct. 31, 2006.