Hypertension is the medical term for a raised blood pressure. It may occur on its own, as part of another syndrome, or may have no identifiable cause. It may lead to severe complications if untreated or inadequately controlled.
JUST WHAT IS HYPERTENSION?
Blood pressure is a measure of how much resistance the heart has to work against with each heartbeat. The actual measurement reflects
- the pressure generated by the pump (the heart) during a contraction. This is called the SYSTOLIC PRESSURE, and is the first ( top) number recorded
- the resistance of the pipes (the aorta and arteries) into which the blood must be pumped. This is the DIASTOLIC PRESSURE, and is the second, usually lower number recorded. The diastolic pressure thus gives an indication of the back-pressure exerted on the heart during its relaxation phase between contractions.
Just as some pumps are more powerful, so some hearts can generate more or less pumping force, for various reasons. Small, rigid pipes will provide more resistance than will large, flexible pipes.
Maintaining a normal BP relies on the interplay of various organ systems and the substances they secrete/activate. Under normal circumstances, the cardiovascular system is able to change BP to meet the needs of the body at any given time. For example, a rise in blood pressure with exercise is a normal response, and the BP should then return to normal values within a few minutes of stopping the exercise. Failure to do so is an indication of a problem in the regulatory mechanisms. Blood pressure normally decreases at night and during sleep: the high incidence of heart attacks in the early morning is thought to be due, at least in part, to “non-dipping” of the BP in some persons. The sustained raised BP, even during sleep, places an increased workload on the heart.