Song Yi Shin, M.S.

How can you improve your vascular health? You would undoubtedly answer that it is the exercise, and it is true. Your arteries deliver blood and oxygen to organs and skeletal muscle. When you start to exercise, your legs would need more blood to match the metabolic demands. At rest, a majority of your blood volume is in your veins. But during exercise, blood flow through tissues change dramatically, with 85% of blood going to your active muscles through arteries in healthy subjects. However, regardless how fit you are, exercise capacity and various physiological body systems decrease with aging. In other words, old subjects have limited abilities to redistribute blood flow in terms of exercise tolerance. It has been shown that exercise duration, grade and peak VO₂ are all lower in the old population (age 60-72) compared to the young population (age 20-40). It is due to inabilities to increase blood flow because of age-related vascular dysfunction. The exact mechanisms that make the vessels deleterious is not known, however, recent studies indicate that proteins responsible for mechano- force transduction are disrupted by aging. Exercise training has been shown to be effective in mitigating age-related alteration. Our laboratory has investigated that possible mechanism that is resulted from exercise training with an animal model. With the isolated arteries, we mimic the pressure that is present during exercise. In our previous research, it turned out that an acute increase in pressure has beneficial effects on vascular function in old animals. However, we still do not know if those beneficial effects are due to endothelium or vascular smooth muscle. Thus, we will examine the vascular function without endothelium in the next experiment to understand the proposed mechanism. You may think that if high pressure has protective effects on vascular dysfunction, it is also possible that hypertensive subjects tend to have healthy vessels. The answer is no. Hypertension patients have higher pressure chronically, but what we are investigating is the short-duration effect of high pressure, just like in exercise!