The heart is a vital organ that is often misinterpreted and misunderstood when it comes to physical activity. The left side of the heart is a pressure pump and the right side is a volume pump. In order to increase the efficiency of the heart, we want to be able to fill up the right side of the heart with as much blood as possible to increase our cardiac output to send oxygen-rich blood to the body. When doing cardiovascular training, this is the adaptation that occurs. When doing strength training, the change is occurring to the left side of the heart, the pressure pump. The myocardium of the left ventricle, the wall of the lower left chamber, results in greater thickness due to the pressure being placed on the heart to pump blood to the muscles. THIS is the very reason we NEED to do cardiovascular AND strength training. Just a reminder that exercise alone does not result in a healthy lifestyle, diet plays a major role as well. Without a healthful and balanced diet, the heart may have to work harder due to atherosclerosis, plaque build-up in the blood vessels, which inhibits blood flow to and from the heart.