WHAT IS HYPERTENSION?
Hypertension is derived from two root words; Hyper meaning High and Tension meaning Pressure. Hypertension simply means high blood pressure. Pressure is the force generated when the heart contracts and pump blood through the blood vessels that conduct the blood to various parts of the blood.
Although hypertension does not mean or result from excessive emotional tension, but evidence shows that stress and emotional tension do cause increase in blood pressure, and if continuous, could be sustained.
High blood pressure is therefore generally defined as a blood pressure exceeding 140/90mmHg confirmed on multiple occasions. The top number (140) is called the SYSTOLIC PRESSURE, and it represents the pressure in the blood vessels (arteries) as the heart contracts and pump blood into circulation. The bottom number (90) is called DIASTOLIC PRESSURE, and it represents the pressure in the blood vessels as the heart relaxes after contraction. These figures measured in millimeters of Mercury (mmHg) reflect the highest and lowest pressures the heart and blood vessels are exposed to during circulation. The generally accepted normal value for blood pressure is 120/80mmHg. Above this value but less than 140/90mmHg is not considered to be hypertensive yet but signals danger, it is therefore called High normal.
An elevation of the blood pressure (Hypertension) increases the risk of developing Heart (Cardiac) diseases such as Heart Failure and Heart attack, Kidney diseases, Vascular diseases like athelosclerosis (hardening and narrowing of blood vessels), Eye damage and Stroke (brain damage).
These complications called End organ damage arise as a result of long standing (chronic) hypertension. But victims of hypertension are not aware, at an early stage, that they 高血壓 have the disease, until these complications start appearing. This is because hypertension shows virtually no signs/symptoms at the early stage. For this reason, it is generally referred to as the ‘Silent Killer’.
The damage caused by hypertension increases in severity as the blood pressure increases. Based on this hypertension can be classified as follows:
CATEGORY SYSTOLIC(mmHg) DIASTOLIC(mmHg)
Normal Less than 130 Less than 85
High Normal 130 – 139 85 – 89
Mild Hypertension 140 – 159 90 – 99
Moderate Hypertension 160 – 179 100 – 109
Severe Hypertension 180 – 209 110 – 119
Very Severe Hypertension Greater than 210 Greater than 120
Borderline Hypertension is defined as mildly elevated blood pressure that is found to be higher than 140/90mmHg at some times and lower than that at other times.
Patients with borderline value need to have their blood pressure monitored more frequently. They also need to assess end organ damage to be aware of the significance of their hypertension.
It should, however, be emphasized that patients with borderline hypertension have a higher tendency to develop a more sustained hypertension as they get older. They stand a modest risk of having heart related diseases. A close monitoring of their blood pressure and lifestyles could be very useful in this regard.