BLOOD PRESSURE   9 Chapter Four Reducing your risk factors, eating a healthy diet, and taking the right supplements all contribute to healthy blood pressure. But that’s only part of the story. The human body was built to move, and we can decrease our blood pressure by increasing our activity level. Sadly, we’re a culture of couch potatoes, with fewer than 50 percent of us exercising on a regular basis (at least three hours per week). We all want to get fit, but we don’t want to get moving. However, conquering our inertia leads to a big payoff. Consistent physical activity helps us control blood pressure in a number of important ways. Positive Effects of Exercise It’s well-known that exercise can have a positive effect on blood pressure. ­ Consistent vigorous physical activity promotes relaxation and deep restful sleep. In addition, physical activity triggers the release of endorphins, “feel-good” brain chemicals that act as natural opiates. Research indicates that vigorous aerobic ­ exercise can increase endorphin levels five-fold. Aerobic exercise also chips away at the resistance to blood flow by dilating the millions of arterioles in the body. In addition, physical activity also lessens the heart’s workload by training it to pump more efficiently. Researchers from the National Heart, Lung, and Blood Institute in Bethesda, Maryland, looked at the effect of treadmill exercise on the cardiovascular health of 72 office and laboratory