By Kenneth Gardner
Blood pressure is the force exerted by the blood on the walls of the arteries. Optimal blood pressure is 120/80 or less, while blood pressure above 140/90 is referred to as high blood pressure or hypertension. High blood pressure is one of the major risk factors for heart disease, the main cause of death worldwide.
About 90 per cent of all high blood pressure which is referred to as essential is persistently high blood pressure that cannot be attributed to any specific organic cause. The remaining 10 per cent or secondary high blood pressure is attributed to many pathological conditions such as narrowing of the arteries and their reduced elasticity, kidney disease, high sodium intake in the diet and increased secretion of hormones that promote the retention of salt and water by the kidneys. Increased retention of water in the body ultimately increases blood volume and inevitably the blood pressure.
Other risk factors for high blood pressure include increase in age, lack of regular exercise, being overweight, stress, a high-fat diet and heredity. High blood pressure increases the risks of developing coronary heart disease, congestive heart failure, stroke, kidney failure, osteoporosis and premature death. High blood pressure does not hurt nor does it make us feel sick. So if it is not monitored and kept under control years could go by before we realise that we have a serious problem, thus its description as the silent killer.
The higher the blood pressure the greater the risk of coronary heart disease and stroke. Sustained high blood pressure over time increases the likelihood of damage to the blood vessels, especially when it is associated with high levels of fat in the blood. Essentially, the arteries lose their elasticity, which creates resistance to normal blood flow, and the constant high blood pressure wears away at the walls of the heart and blood vessels.
Thus the workload of the heart is increased to overcome the resistance of the high blood pressure. With this added burden the heart muscles often grow larger, but they become weaker and less efficient. The enlarged heart becomes overextended and has difficulty meeting the demands of pumping blood against high pressure, thus the heart has to work much harder which often results in congestive heart failure.
Generally persons with lower blood pressure tend to have lower incidences of cardiovascular disease. Likewise, the risk of early mortality is lower in persons who are physically fit with blood pressure in the optimum range.
The importance of physical activity in weight management, improved blood composition, circulation and cardiovascular health are well established. Thus, the corrective effect of physical activity on the risk factors of high blood pressure can be attained and maintained. Regular exercise, optimum caloric and sodium intake are recommended to achieve the best results in attaining and maintaining optimum blood pressure.
Dr Kenneth Gardner is an exercise physiologist at Holiday Hills Research Center; email: firstname.lastname@example.org.