ABSTRACT
Energy is required by all cells. In order for you to jump, throw, run, swim, or cycle, skeletal muscle cells must be able to extract energy from energy-containing nutrients such as carbohydrate and fat. Energy is also needed for other bodily functions such as circulation, digestion, absorption, glandular secretion, neural transmission, and biosynthesis, to name just a few. Although the body has some energy reserves, most of its energy must be obtained through nutrition. Most cells possess chemical pathways that are capable of converting energy-containing nutrients into a biologically usable form of energy. This metabolic process is termed bioenergetics. During exercise, the energy requirement increases, and energy provision can become critical. In fact, the inability to transform energy contained in foodstuffs rapidly into biologically usable energy would limit sports performance. In athletes, carbohydrate depletion represents one of the most common causes of fatigue. People with a defects in energy metabolism cannot tolerate high-intensity exercise. For example, those with McArdle’s diseases,
Energy and its transformation 137 ❚
Energy consumption 140 ❚
Energy transformation 145 ❚
Control of energy transformation 153 ❚
Summary 159 ❚
capacity. The amount of food energy that is available, coupled with the ability to transform the food energy into the form that is usable by body cells is what dictates how well the body responds to physical stress. As such, it is imperative to understand what energy is and how the body acquires, converts, stores, and utilizes it.
