Physical inactivity and sedentary lifestyle predispose individuals to countless different chronic diseases, including cardiovascular disease and diabetes mellitus. Low cardio respiratory fitness intensifies the risk for mortality in individuals with and without underlying chronic disease. On the contrary, recent findings reveal that life long daily aerobic exercise efficiently attenuates risk for cardiovascular disease and diabetes mellitus. In fact, the differences in determinants of cardiovascular risk, namely heart left ventricle and atrium compliance, between exercising and sedentary adults are so profound that some speculate that excessive morbidity associated with aging may be more related to sedentary lifestyle than senescence. The pathophysiology through which sedentary lifestyle accelerates disease progression appear to be related to arterial stiffening and insulin resistance. It is unclear whether the negative influence of physical inactivity on the determinants of cardiovascular risk emerge only late in life or whether they are present on young individuals. It is important to determine whether sedentary lifestyle whether physically inactive, young, otherwise healthy men and women show different antecedents of cardiovascular disease - such as arterial stiffness, vascular endothelium relaxation and insulin sensitivity relative to their physically active counterparts. A study by J.M. McGavok et al (2005) showed that physically inactive individuals are characterized by reduced arterial compliance and insulin sensitivity relative to their highly exercising peers, which are independent of changes in conventional risk factors for cardiovascular disease. Their research consisted of 135 otherwise healthy young men and women aged 20 to 40 years who were grouped based on their physical activity status - if they do not perform any aerobic exercise at all, physically active or are endurance-trained. Arterial compliance assessed by measuring diastolic pulse wave and vasodilation was determined by echocardiographic examination of the brachial artery. The homeostasis model was used to examine insulin sensitivity and glucose breath test for insulin resistance. They found that artery compliance was significantly lower in sedentary subjects than in physically active or endurance trained subjects. Vasorelaxation did not vary across the groups. The sedentary group was statistically showed a higher insulin resistance compared to their endurance trained counterparts. A number of research programs show that age related decrease in arterial compliance and vascular relaxation are ameliorated with life long endurance training. Aside from the prophylaxis of cardiovascular disease achieved by chronic daily aerobic exercise, stamina training is also the foundation in the prevention of diabetes. In a general perspective, the similarities between the cardiovascular and metabolic responses to chronic aerobic exercise and prolonged physical inactivity are quite astonishing. Evidence shows a close relationship between metabolic dysfunction and cardiovascular disease. One of the underlying biochemical mechanisms through which sedentary lifestyle leads to cardiovascular disease is through a progressive increase in insulin resistance. There seem to be an interaction between insulin sensitivity and cardiovascular health. The findings of McGovak et al suggest that there is an increasing need for regular physical activity to prevent the occurrence of cardiovascular disease in persons across all ages. Cardiovascular and metabolic outcomes associated with sedentary lifestyle are only marginally improved in individuals who perform aerobic exercise less than 45 minutes at a moderate intensity, 3 to 4 days per week. Individuals must perform vigorous physical endurance training more frequently and for longer periods of time to achieve a more favorable outcome. Men and women should do regular vigorous aerobic exercise across ages to prevent cardiovascular disease. |
