Oxygen carries blood through the whole body, including the organs and brain. The proper carriage of oxygen thoroughly cleanses and nourishes the body. Exercise that causes stressed breathing, that is, fully maximizing to your heart beat level, does not allow the oxygen to flow fully through your body. The flow is stunted and shallow because you are only taking in a minimal amount of fresh oxygen and your muscles are tight and restrained. The blood pools below the heart because the body is so stressed it cannot pull the blood higher.
Heart attacks can occur.
Safety Factors Exercising safely is an integral part of the soft method. Moderate increase in heart rate, that is, breathing harder than normal but not so hard that you can't talk rather comfortably, allows fresh oxygen to flow smoothly through your entire body and all its parts carrying the necessary and proper amounts of blood with it and rinsing out the toxins. The muscles are not constricted so that blood may flow through and allow them to work to their maximum capability. It just strains your body and allows toxins to stay in such places as your organs, muscles, tendons, and ligaments. These toxins often cause cramping, which is immediately noticeable.