The probability of the Heart attack is higher in individuals that undergo intense exertion including both the psychological stress and physical exertion. It is more pronounced where the exertion is more intense than the level of the individual performance. In fact, the period of intense exercise and subsequent recovery is associated with six fold higher myocardial infarction rate as compared with relaxed time frames for people who are physically fit. This rate of myocardial infarction increases to 35-fold higher in persons with poor physical condition. It happens because of the increased arterial pulse pressure during the stretching and relaxation of arteries with every heart beat. This led to the increased mechanical “shear stress” on atheromas leading to plaque rupture.
Another major cause of heart attack is the acute severe infection like pneumonia that can trigger myocardial infarction. The link between Chlamydophila pneumoniae infection and atherosclerosis is under study. The atherosclerotic plaques are found to contain this intracellular organism but this evidence is not conclusive to become a causative factor. Also, the treatment of patients with antibiotics does not lead to decreased risk of heart attacks or any other coronary diseases.
The timing of heart attack also varies as per the circadian rhythm. It has been observed that there is increased incidence of heart attack in the morning hours and in particular at 9 am. Some investigators opined the fact that the ability of platelets to aggregate changes as per the circadian rhythm. Others have theorized that this increased incidence of heart attack in morning hours might be related to the circadian variation in production of Cortisol. This in turn affects the concentrations of different cytokines and various mediators of inflammation. The study of the causes of the incidence of Myocardial Infarction can helps the individuals to remain alert of any symptoms and take preventive measures.