A Publication of WTVP

We know an effective exercise program can help produce improvements in many different systems of the body such as the muscles, bones, heart, and lungs. When considering the relationship between the skeletal muscles and the cardiac muscles, an old Chinese proverb comes to mind: “When you ask the right questions, the answers reveal themselves.” 

When we perform activities such as walking, jogging, stair climbing, biking, etc., what performs the work?

Is it the heart and lungs? No, it’s the muscles. The stimulus of exercise can only be applied to one system directly—the muscles. It’s only through muscular work that we gain access to the cardiovascular system, bones, tendons, ligaments, etc. We can’t address these systems directly or independently of the muscles. How do you work the heart and lungs and stimulate cardiovascular fitness? Do you put them on a treadmill or stair stepper? Do you place the heart and lungs on a bicycle and ask them to pedal away? Or maybe you prefer to just send the heart and lungs out for a brisk walk? Of course not.

The heart and lungs aren’t capable of performing such work. During exercise or physical activity, the heart and lungs have to work harder only because they’re forced to respond to the increased demands being placed upon them by a muscle’s increased need for blood, oxygen, and nutrients, as well as the need for the removal of waste products. George Sheehan, M.D., cardiologist (known as the guru of running), has stated, “No matter what you have been told, running primarily trains and conditions the muscles; the other organs merely assist in realizing this functional potential. Almost all of the improvement in performance occurs because of the circulatory changes in the muscles and changes in the muscle cells.” 

Do your heart and lungs know which activity they’re performing?

Of course not. All the body knows is that it’s performing increased work and that its demands have also increased. The body has no way of determining whether you’re performing aerobic activities or strength training. 

What does this teach us about the relationship between the skeletal muscles and cardiac muscles with respect to cardiovascular performance?

If you want to find the best way to work both the muscles and the cardiovascular system, it all starts with finding the best way to work the muscles. Any positive changes made on the skeletal muscles will simultaneously improve all other physical functions. Since strength training provides a much more thorough level of muscular work than any aerobic activity, it’s apparent a properly applied strength training program is capable of creating the best stimulus for improvements in cardiovascular efficiency. Therefore, the primary aim of an exercise program should be muscular fitness. IBI