Maladaptation of cardiac and skeletal muscle in chronic disease : effects of exercise

The human genome is adapted for daily physical activity (85). Thus, a sedentary lifestyle is capable of promoting detrimental consequences to human health. The linkage between lack of sufficient physical activity and the development of modern chronic disease began to evolve only in the second half of the 20 century. This relationship was initially documented in London where men, who were more sedentary at work or during leisure time, had higher rates of coronary heart disease (242; 243). A multitude of other published reports have since confirmed the health hazards of maintaining an inactive lifestyle (40; 329). In addition, modern chronic diseases attributed to physical inactivity now represent a major burden on direct health care costs in the United States which totaled 83.6 million dollars in 2000 (55; 102). The importance of physical activity has become more apparent and it is now recommended by the US Surgeon General that “every U.S. adult should accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week” (264). Furthermore, physicians are also being recommended to prescribe regular