It is established that physical activity can contribute to improvements in health and a much healthier lifestyle. Countless researches have shown the connection between lack of physical activity and the presence of certain illnesses including terminal illnesses. These researches have also demonstrated the possible mitigating effects that physical activity can have on helping to delay or prevent these illnesses. Furthermore the frequency of participating in physical activity is of importance since, as Pratt, Macera and Blanton (1999) point out, regular physical activity contributes to an improved lifestyle and avoiding chronic illnesses.
Lack of physical activity has been closely linked with cardiovascular disease. Additionally studies are showing a negative correlation between participating in regular physical activity and morbidity and mortality from several diseases including diabetes, cancer, heart disease, hypertension, hypercholesterolemia and osteoporosis. Lee and Paffenbarger (2000) found that both men and women who are involved in some amount of physical activity daily have significantly lower rates of mortality and less cardiovascular events than those who are sedentary, i.e. those who refrain from any physical activity.
Overall it is estimated that between 27 and 40% of preventable deaths from coronary heart disease are as a result of a sedentary lifestyle (Macera & Powell, 2001; Steffen et al. , 2006). Physical Activity Requirements Since physical activity has been noted to be of such significance to improved health in the general population experts have attempted to quantify the type and the amount of physical activity that would be considered adequate.
At the national level the U. S. Department of Health and Human Services encourages each person to comply with recommended standards of physical activity, i. e. persons should aim to satisfy the requirements for either moderate to vigorous physical activity (USDHHS, 1996). Meeting requirements also involves physical activity that satisfies minimum duration. Vigorous physical activity is categorized as being involved in activities that cause the person to breathe heavily.
Pratt et al. (1999) adds that the intensity of the activity should be equivalent to approximately 50% or more of their cardiorespiratory capacity as determined by their age and gender. Such activities should also cause the participant to sweat. Additionally the person has to be involved in physical activity for more than two times per week and each physical activity session should last between 20 and 30 minutes each session (Hawkins, Cockburn, Hamilton & Mack, 2004, p. 254; Pratt et al. , 1999). Walking is one of the more popular vigorous physical activities (Rafferty, Reeves, McGee & Pivarnik, 2002).
Moderate physical activity, on the other hand involves involvement in exercise that does not cause the participant to breathe hard. Participants must undertake these activities for at least five times each week. Each physical activity sessions should also last between 10 and 30 minutes (Hawkins et al. , 2004; Pratt et al. , 1999). Pratt et al. (1999) indicates that sessions can be less frequent or vary in duration each session but the total composite time involved weekly should amount to at least 150 minutes.