“To explore how physical activity helps but doesn’t entirely prevent cardiovascular diseases, let’s return to the trinity of intertwined factors that are the root causes of the problem: high cholesterol, high blood pressure, and inflammation. Cholesterol. A cholesterol test usually measures the levels of three molecules in your blood. The first is low-density lipoprotein (LDL), often termed bad cholesterol. Your liver produces these balloon-like molecules to transport fats and cholesterol throughout your bloodstream, but some LDLs have a harmful tendency to burrow into the walls of arteries, especially when blood pressure is high. These intrusions cause an inflammatory reaction that generates plaques. The second type of cholesterol is high-density lipoprotein (HDL), sometimes called good cholesterol, because these molecules scavenge and return LDLs back to the liver. The third type are triglycerides, fat molecules that are floating freely in the bloodstream and a signpost for metabolic syndrome. To make a long story short, diets rich in sugar and saturated fats contribute to cardiovascular disease because they promote high levels of plaque-forming LDLs. Conversely, physical activity helps prevent cardiovascular disease by lowering triglycerides, raising HDL levels, and to a lesser degree lowering LDL. Blood pressure. A blood pressure test gives you two readings: the higher (systolic) number is the pressure your heart’s main chamber overcomes when it squeezes blood throughout your body; the lower (diastolic) number is the pressure your heart experiences as its main chamber fills with blood. By convention high blood pressure is a reading greater than 130/90 or 140/90. Blood pressures above these values are concerning because, unabated, they damage the walls of arteries, making them vulnerable to invasion by plaque-inducing LDLs. As we already saw, once plaques start to form, blood pressure can rise, potentially stimulating yet more plaques. Chronically high blood pressure also strains the heart, causing it to thicken abnormally and weaken. By forcing more blood to flow more rapidly through arteries, physical activity stimulates the generation of new arteries throughout the body and helps keep existing arteries supple, protecting against high blood pressure. Inflammation. Plaques don’t form out of the blue but instead occur when white blood cells in the bloodstream react to the inflammation caused by LDLs and high blood pressure. Chronic inflammation also increases one’s likelihood of developing plaques from high cholesterol and blood pressure.40 And, as we have previously seen, while inflammation is caused by factors such as obesity, junky diets, excess alcohol, and smoking, it is substantially lowered by physical activity.”