Most remodeling projects come with a big price tag, but here’s one that does not. Remodeling your arteries – in particular, the coronary arteries that supply blood to your heart and the carotid arteries that feed your brain – is essentially free.  All they need is regular activity.  Here’s how activity works to improve arterial health and greatly reduce the risk of cardiovascular disease.

Your arteries are the blood vessels that take oxygenated blood away from the heart and deliver it to the rest of your body, including heart muscle (these are the infamous coronary arteries, which, when clogged or in spasm, cause chest pain or heart attacks).  Arteries are small muscular hoses in which blood flows in one direction (away from the heart), and which must sustain the stress of the blood pushing against the artery walls with each heartbeat.  This form of stress in an artery is called shear stress, because it is caused by the flow of blood along the interior wall of the artery (parallel to the arterial wall, as opposed to perpendicular to the artery wall).

Exercise (especially regular moderate to vigorous activity) promotes two important changes in how the arteries function. The first is called a functional response, and it occurs soon after someone starts regular activity.  The essential functional adaption is greater output of nitric oxide (NO) by the arterial wall itself.  NO helps to keep the blood vessel relaxed (thus lowering blood pressure), reduce inflammation in the blood vessel, lower the likelihood of clot formation, and limit the buildup of abnormal thickness of the arterial wall.  You can read more about the beneficial effects of NO at (http://www.cvphysiology.com/Blood%20Flow/BF011.htm).  And, no, you cannot get this by taking a worthless NO supplement.

The second adaptation is a structural response, in which the artery actually remodels in response to repetitive, continuous exercise (such as cycling, vigorous walking, running, etc.).  This remodeling causes the artery to increase in diameter (including, especially, larger ones, such as the femoral, carotid, and bigger coronary arteries).  Hence, shear stress goes down because the blood is flowing through a larger diameter hose.  Another structural response to strenuous exercise is that the arteries remain more supple and flexible, possibly because your body puts down more elastin, which contributes to arterial flexibility (Seals).  Data from the Netherlands show that the (carotid) arteries of young people who work out hard are less stiff in early middle age (mid 30s) than the arteries of sedentary men and women of the same age, which portends a substantial reduction in the risk of cardiovascular disease (van de Laar).  This benefit did not occur in young people who got only light to moderate physical activity.  So, for example, fast walking/light jogging would reduce arterial stiffness in ways that slow/moderate walking would not.

Importantly, these changes tell us that having a high level of conditioning, from a vigorous physical activity habit, produces cardioprotective changes that go beyond the conventional benefits of improving glucose metabolism or lowering triglycerides and cholesterol.  Indeed, the author of one review paper notes, “each exercise bout may be thought of as providing a direct dose of vascular medicine (Green).”

Going from sedentary to active is good, but going from active to very active, and then to fit is important. Heart health advocates often call high blood pressure the silent killer because of its lack of symptoms.  Well, in this case, we see that you have a silent remodeler working in your cardiovascular system every time you exercise, especially when you exercise hard aerobically and do so repeatedly.  To achieve these effects, build your tolerance slowly and make aerobic workouts longer before making them harder.  Then, increase intensity in simple ways: insert periods of faster running when you jog, or, do some jogging or very fast walking when you walk.  Finally, if you walk, cycle, or run outdoors, add hills to your activity.  Your remodeled arteries will add to your quality of life by reducing your risk of cardiovascular disease, our nation’s number one cause of death…something important to think about during Heart Month.

(Sources: Green, DJ, Exercise training as vascular medicine.  Exercise and Sport Sciences Reviews.  Oct. 2009. 37:4; 196-202; and, van de Laar, R, et al.  Lifetime vigorous but not light to moderate habitual physical activity impacts favorably on carotid stiffness.  Hypertension.  Dec. 7, 2009 [published online].  See also Seals, D, Habitual compliance and the age-associated decline in large artery compliance. Exercise and Sports Sciences Reviews. April 2003. 31:2; 68-72.)