Blood pressure is quite simply explained as the lateral pressure exerted by blood on the walls of vessels in which it is contained and flows through. Of the two blood vessel systems, arterial (thick-walled) & venous (much thinner), the pressure measures relatively far more in arteries than in veins. High blood pressure (hypertension) or BP occurs when excessive force is exerted against the arterial walls as the heart pumps blood (systole). This dreaded ‘silent disease’ has, most of the times, no obvious symptoms until it has reached an advanced and almost chronically established state, at which point, it may cause headache, lightheadedness, ringing in the ears, and possibly rapid heartbeat (tachycardia) upon even minor exertion. If it remains uncontrolled (and undetected), it may well lead to a heart attack, stroke, eye damage, or even renal failure over a period of time.
The modern (digital) BP measuring instruments have all but replaced the olden mercury column type (sphygmomanometer) rather bulky instrument. The digital instruments are very useful gadget to monitor BP quite easily at home or during our travels outside. It operates on a few batteries, which last quite a while. These digital machines are fully automatic, one just has to wrap the inflatable cuff around the upper arm. Readings are readily available for systolic, diastolic pressure vales, as also for the pulse rate and rhythm (regularity). The machine stores quite a few readings to let the user evaluate his BP over a period of time.
In most people, the cause of hypertension is not known, and it may be classified as primary or essential. In about 5-7% of the cases, it may result from underlying renal disease, some hormonal imbalance, or some other identifiable organic factor. This then is known as secondary hypertension. Predisposing risk factors have been identified as (i) obesity, (ii) a family history of hypertension, or even a cerebral stroke at an early age. Besides obesity and sedentary mode of life, a high-salt diet is supposedly considered as the causative reason for hypertension, especially in genetically predisposed persons. Epidemiologically, African-Americans show a higher incidence of hypertension than whites. Women are supposedly less prone to high blood pressure than men, but, at the same, pregnancy and use of oral contraceptives may increase their susceptibility as well. The disease affects an estimated 55 million Americans of all age groups – young and old.
Because there usually are no symptoms, hypertension is most often diagnosed during a routine medical examination or a special screening programme. BP is normally measure with an instrument called as sphygmomanometer. We’re not going to discuss the details of this clinical instrument, nor of the BP-measuring procedure using this equipment at this web site. Quite a few physicians and clinics/hospitals still use this instrument, but, for home-monitoring purposes, this rather bulky and tedious-to-use equipment has been replaced with a far easier ‘digital’ apparatus, which one can regularly use all by oneself.
Normal blood pressure values for healthy adults are 120 (systolic, when the heart is contracting) / 80 (diastolic, when the heart is refilling). Usually this difference between the upper & lower value is called as ‘pulse pressure‘. It is always (120 minus 80) that is 40 or more. Reducing ‘pulse pressure‘ may indicate serious issues with one’s circulatory health, and may cause functional heart failure, or may even prove fatal if it intensifies suddenly. Over a period of 24 hours, blood pressure values may vary considerably. It is usually lowest during sleep and highest during early morning, mostly owing to epinephrine surge in the morning. Anger, stress, anxiety or stimulation (caffeine, nicotine, alcohol) make BP shoot a bit. As said earlier, a resting BP value of 120/80 or near about is considered normal for adults, and a consistent reading of 140/90 or higher over a period of time is classified as clinical hypertension. However, to make a right diagnosis, BP must be measured a number of times over several weeks, unless the initial reading itself is dangerously high, e.g., 160/100 or higher. Wearing of a an ambulatory 24-hour BP monitor may be recommended in some cases. This device continually measures and records blood pressure. Besides all these clinical procedures, if any complication related to hypertension, such as a hypertrophied heart or kidney damage is suspected, additional, standard cardiology tests may be required for a reasonable clinical evaluation of the patient.