I have been a Physical Therapist for 20 years and exercise and nutrition junky my entire life. I have read books, magazine, tried different exercise programs and just about every sports nutrition product on the market. I have learned, (yes, finally becoming very wise) that exercise is literally a science. When you understand the science you can get very predictable results. I am here to provide some insights on several concepts of exercise science and ways to improve your cardiovascular endurance to help you improve and reach a new level of physical being and fitness.
Best Tips to Improve Exercise Efficiency
Understand Aerobic Metabolism
When you perform endurance exercise or activities, your body requires a continual supply of fuel. Our bodies convert food nutrients into chemical energy during the digestion/absorption process. Then at the cellular level, our bodies convert these stored chemical energy sources into mechanical energy, which is how we perform exercise or work.
The Adenosine Triphosphate (ATP) needed for muscle work can be produced from either aerobic (with oxygen) metabolism or from anaerobic (without oxygen) metabolism. The aerobic metabolism of nutrients refers to the oxidation of glucose or glycogen molecules and fatty acids to form ATP, this process is called aerobic glycolysis. This metabolic pathway requires a continuous supply of oxygen and nutrients. The nutrients are in the forms of carbohydrates, fatty acids or proteins. The breakdown of carbohydrates provides the largest nutrient source of energy to working muscles. The liver and muscle cells store the carbohydrates as glycogen, a starch built by linking glucose molecules together. An individual glycogen molecule may contain hundreds to thousands of glucose molecules linked together by weak bonds. During work activities, individual working muscle cells break down the glycogen molecules in process called glycogenolysis. This process provides glucose, as an energy source, to the working muscles. Glycogenolysis can also occur in the liver, the free-floating glucose and fatty acids are then delivered to the working muscles by the blood supply.
Aerobic glycolysis can be sustained as long as there is a sufficient supply of oxygen and glucose. Total glycogen stores are limited and can be depleted from the body within a few hours in cases of prolonged work. Proteins, which are comprised of amino acid chains, contribute only a small percentage of usable energy during work. Proteins are metabolized for energy by two different processes. The proteins can either be converted to glycogen in the liver, then transported to working muscles in the form of glucose, or the protein amino acids can be directly converted to energy inside the working muscle cells via the Kreb's Cycle, a complex metabolic pathway.
In addition to nutrients, aerobic metabolism utilizes oxygen. Small amounts of oxygen are found within the muscle cells attached to the muscle proteins, however the majority of oxygen is carried to the muscle cells via blood cells from the circulatory system. A cardiovascular response to increased workload is to increase the amount of blood flowing to active muscle. However, it can take almost one minute for this response to be activated. Therefore, at the onset of most industrial tasks, or in cases of quick-high intensity tasks, it is not always possible to have adequate blood flow available to working muscles. When this occurs, the muscles switch to anaerobic metabolism.