The Causes and Consequences of High Blood Pressure

High blood pressure (hypertension) is commonly caused by;

1. Diseases of the circulatory system such as atherosclerosis, which increases resistance to blood flow by reducing blood vessel elasticity and diameter.
2. Conditions which result in fluid retention, such as kidney failure.
3. Chronic stress.

High blood pressure has two main deleterious effects on health.

1. It increases the work load placed on the heart by creating greater aortic pressures for the left ventricle to overcome.
2. It may cause direct damage to the blood vessels.

The greater work load placed on the heart may lead, in the long run, to enlargement or thickening (hypertrophy) of the heart muscle (myocardium). Such an enlargement is deleterious in a number of ways. Firstly, the increased heart size is not always matched by increased capillarisation (blood vessel density), and this leads to the development of an oxygen shortage in some sections of heart.

High pressure in the coronary arteries also contributes to atherosclerotic development. The high pressure blood flow against the arterial wall leaves scared areas which may become sights for atherosclerotic deposits. These deposits can build up to the degree that they cause near total blockage of the vessel, leading to ischemia (oxygen shortage) in the area normally supplied by that capillary. The scared vessel wall can also trigger blood clotting which can cause strokes, organ damage and heart attacks.

Some conditions resulting in high blood pressure can be brought under control by exercise. Many believe that as an artificial 'stressor' exercise renders the heart less responsive to the resting levels of various 'stress' hormones (adrenalin and noradrenalin for example) which contribute to increases in blood pressure and are often associated with hypertension.

Commonly the weight loss associated with exercise is sufficient to lower blood pressure to some degree. Indeed, the most common medical advice given to the slightly overweight, moderately hypertensive individual is to exercise in order to lose weight. Nevertheless, it must be noted that some hypertensive conditions are not responsive to exercise.

Hypertensive individuals should be encouraged to obtain a medical clearance prior to the commencement of an exercise program. Once approval has been gained aerobic exercise is the most highly recommended training mode, particularly when weight loss is also desired.

Because of the acute increases in blood pressure associated with heavy lifting, resistance training should be carried out with caution by people with advanced cardiovascular disease (especially that involving some deterioration of the blood vessels). Extreme elevations in blood pressure occur when heavy loads are lifted repeatedly to the point of muscular failure in exercises utilizing a number of large muscle groups such as the squat, leg press or dead lift. However, appropriately designed resistance training programs are quite commonly and effectively used in the rehabilitation programs of coronary heart disease patients.

In health screening tests carried out in the fitness centre low blood pressure is of little concern. The most common consequence of low blood pressure is postural hypotension which exhibits itself as dizziness associated with moving from sitting or lying to a standing position. This is only harmful if an individual faints and hurts themselves whilst falling.

For individuals who have exhibited postural hypotension movement from lying to standing should be done in relatively slow stages.