Hypertension is defined as elevated blood pressure in the arteries. As a person’s heart muscle contracts, it pushes blood into the major arteries and then on through the capillaries to the veins. It is the pressure within the arteries that is measured in blood pressure readings.
The first value of this measurement is called the systolic pressure which measures the pressure in the arteries while the heart muscle is in the peak of contracting. This normally reaches a value of 100 to 130 mmHg (millimeters of mercury in young adults.
The second value of this measurement is called the diastolic pressure which measures the beats of the heart while it is resting. This pressure is normally between 70 and 80 mmHg. A normal blood pressure might be expressed as 110/70 (110 over 70). These pressures both increase with age, with systolic pressure tending to rise more than the diastolic pressure.
Blood pressures vary from person-to-person and throughout the day. Generally, a systolic pressure higher than 140 mmHg and a diastolic pressure higher than 90 mmHg are used as thresholds to define hypertension in adults.
In most people who have high blood pressure, a precise cause cannot be identified. But, in some individuals, an underlying cause such as blockage of the blood flowing to the kidney or a tumor in the adrenal gland or hormone imbalance may be responsible for the blood pressure problem.
High blood pressure often has no physical symptoms. It is dangerous and can actually do damage to the body’s organs (the heart, the brain, the kidneys) before it is diagnosed. Hypertension can silently, but directly lead to a heart attack, stroke, congestive heart failure and kidney disease.
For patients with normal blood pressure readings, having it re-checked at a minimum of every two years is important. Patients are considered high risk if they have blood pressure near the top of the normal range, or if they have a family history of high blood pressure. More regular blood pressure checks are strongly recommended for these individuals.
In 90-95% of the cases of individuals who have hypertension, the cause is unknown. It cannot be cured, but it can be controlled. Certain factors that increase the risk of hypertension are: