What is Energy?

For our purposes, energy represents the capacity to do work. Work is one form of energy, often called mechanical or kinetic energy. When we throw a ball or run a mile, we have done work; we have produced mechanical energy.

Energy exists in variety of other form in nature, such as the light energy of the sun, nuclear energy in uranium, electrical energy in lightning storms, heat energy in fires and chemical energy in oil. The six form of energy is; mechanical, chemical, heat, electrical, light and nuclear are interchangable acconding to various laws of thermodynamics. We take advantage of these laws every day. One such example is the use of the chemical energy in gasoline to produce mechanical energy, the movement of our cars.

In the human body, four of these types of energy are important. Our bodies possess stores of chemical energy that can be used to produce electrical energy for creation of electrical nerve impulses to produce heat energy to help keep our boy temparature at 37 degree Celcius ( 98.6 degree Fahrenheit ) even on cold day and to produce mechanical energy through muscle shortening so that we may move about.

The sun is the ultimate source of energy. Solar energy is harnessed by plants, through photosynthesis to produce either plant carbohydrates, fats or proteins, all forms as stored chemical energy. When human consume plants and animal foods the carbohydrates, fats and proteins undergo a series of metabolic changes and utilized to develop body structure, to regulatebody processes or to provide a storage form of chemical energy.

The optimal intake and output of energy is important to all individuals, but especially for the physically active person. To perform to capacity, body energy store must be used in the most efficient manner possible.

Sources>> Williams. M.H (2010) Nutrition for Health, Fitness and Sport . Ninth Edition. McGraw Hill International Edition.