SHADOW TEAM: October 2008

Monday, October 20, 2008

Aerobic Fitness. Its Meaning and Significance

Aerobic Fitness. Its Meaning and Significance

"Aerobic fitness" refers to endurance, or the ability to sustain work for prolonged periods. This is usually experienced in the abilities to walk, run, climb uphill, swim, etc. Most forms of sports, work, recreational and military activities include elements of aerobic fitness. Generally speaking, any activity which lasts less than 12 minutes is not fully aerobic. The term "aerobic" implies that the oxygen necessary to accomplish the work is taken up by the individual during the activity. Strenuous exercise lasting less than 12 minutes includes substantial portions of
In aerobic work, oxygen is obtained from the air and is transferred from the lungs to the blood and then to the muscles via the circulatory system. Maximal oxygen uptake, or maximal aerobic power ( Vo₂ max ) is the indicator of aerobic fitness. Vo₂ max is determined by the measurement of oxygen uptake during the performance of maximal work, typically while running on a treadmill or while cycling. This is done by exercising for at least 12-minutes at submaximal loads, after which the maximal effort is performed for one or two minutes. Oxygen uptake during this time is measured, giving the value of Vo₂ max. As Vo₂ max increases, the level of aerobic fitness also increases. Aerobic fitness is dependent upon age and sex and it can be improved by training. It is highest at ages 18, 19 years in males and 15 to 20 years in females, and it decreases with age in adulthood. In general, males have higher Vo₂ max than females. The main reason for this is that aerobic fitness is directly related to fat-free body weight, which consists mainly of the weight of muscles in the body, and on the average, males have a higher muscle mass than females. As with other physiological functions, there are large individual differences in Vo₂ max of people of the same sex and age. Some people show high Vo₂ max without exercising because of genetic and other factors, while other people who exercise regularly do not show high Vo₂ max .

anaerobic metabolism whereby one uses energy sources stored in the body to perform the work. Since the body's energy sources are limited, anaerobic work cannot last long. Fast runs, lasting 10 to 15 seconds, are mostly accomplished by anaerobic metabolism. With longer exercise time, more aerobic metabolism is involved, and exercise lasting more than 12 minutes is mostly accomplished by aerobic metabolism. Work is performed by the muscles which use oxygen for the combustion of fat and carbohydrates creating the energy necessary to move the body, or to move objects outside the body.