The Effects of Physical Exercise on the Human Body The benefits of physical exercise in humans far out weighs the harmful effects associated with exercise. A prescription of physical activity has been known to delay the onset or prevention of many chronic diseases. An improvement in heart function, lower blood pressure and improve functional capacity is noticed after just a few weeks of exercising. Physical activity will also result in an increase of lean muscle mass, promote weight maintenance, increased flexibility, and a generally stronger more fit individual. Conversely, exercise when preformed strenuously or obsessively it can counteract such positive effects. Bringing up some issues like oxidative stresses, injuries, and compulsive exercise disorders. The Cardiovascular response to exercise occurs quite quickly, during exercise oxygen is demanded in the muscles and the body uses more nutrients, metabolic process speed up, more wastes are created, and the body's temperature increases. With intense exercise hydrogen ion concentrations increase within the muscles and blood this results in an increased pH [16]. A study back in 1976 was done by researchers Hidetaro Shibayama and Hiroshi Ebashi on the effects of long-term physical training of adult men. Shibayama and Ebashi took five healthy males and gave them a routine of a twenty-min treadmill at two-thirds their V02 max for three years, five days a week. After a short while (just twenty weeks) the subjects resting heart rate decreased by five beats a minute, an increase of red blood cell count was shown, and a decrease in average cholesterol levels. Improvement in ventilation efficiency became evident, oxygen intake slightly improved as well, and lactate production decreased. The body's goal is to allow the system to meet increased demands placed upon it by functioning efficiently such as heart rate, stroke volume, cardiac output, aerobic capacity, and blood pressure levels. Not only does the body begin to adapt in a cardiovascular sense but also exercise has been shown to reduce hypokinetic diseases as well as cardiovascular disease. The heart rate is a measurement of how many times the heart beats in a minute. Physically fit people tend to have a lower heart rate and during intense exercise tend to have lower rates as well. A decrease of heart rate at both rest and at fixed intensity of sub-maximal exercise [7] occurs a few months after an exercise program is begun. One's heart rate reflects the amount of work the heart must do to meet an increase of demands of the body when engaged in activity. Heart Rate tends to increase proportionally with intensity oxygen uptake [16]. The amount of blood pumped out during systole is called the stroke volume and is less than the end diastolic volume because the ventricles do not completely empty themselves during systole. At all levels of physical activity stroke volume is increased. There is an improvement in ventricular performance with an increase of plasma volume [4] and a faster peak lengthening the rate of the left ventricle during diastole [6]. Training can improve stroke volume but by no more then about 20%. Due to the decreased heart rate an increase of ventricular filling will result and an increase in ventricular volume and thickening of ventricular walls thus allowing an overall increase in blood volume. [3] The volume of blood pumped in a minute is called the cardiac output and is the product of the stroke volume and the heart rate. Cardiac output is the amount of materials being brought to, or removed from, the bodies tissues measured by the volume pumped out per minute. Cardiac output is equivalent to pulmonary blood flow and how the lungs add oxygen to the blood and remove carbon dioxide from it. The overall cardiovascular response to an endurance based conditioning program is an increase of maximal cardiac output (heart rate x stroke volume) [14]. Maximal Oxygen Uptake (liters per minute) is predominately a function of cardiac output. Improvement in VO2 max (maximal oxygen uptake) depends on age and type of training. There is a limited opportunity to improve aerobic capacity, approximately 10-20% improvement has been noted. Therefore, maximal oxygen uptake has a "central limitation"[10]. Analogously, oxygen consumption can be related to how much gas consumed per kilometer in order to maintain a certain speed. The more oxygen that can be delivered to the working muscles, the greater the energy supply needed, so that the body can travel for a determined distance. Exercise science has determined that you achieve specific training adaptations by exercising at various intensities or percent-ages of VO2 max. Oxygen uptake capacity is measured directly. In essence ther

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