High Blood Pressure
<p><b >Hypertension</b> (<b >HTN</b>) or <b >high blood pressure</b>, sometimes called <b >arterial hypertension</b>, is a <a href="http://en.wikipedia.org/wiki/Chronic_(medicine)" title="Chronic (medicine)" >chronic</a> <a href="http://en.wikipedia.org/wiki/Disease" title="Disease" >medical condition</a> in which the <a href="http://en.wikipedia.org/wiki/Blood_pressure" title="Blood pressure" >blood pressure</a> in the <a href="http://en.wikipedia.org/wiki/Artery" title="Artery" >arteries</a> is elevated. This requires the heart to work harder than normal to circulate blood through the blood vessels. </p>
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Blood pressure involves two measurements, systolic and diastolic, which depend on whether the heart muscle is contracting (systole) or relaxed between beats (diastole). Normal blood pressure at rest is within the range of 100-140mmHg systolic (top reading) and 60-90mmHg diastolic (bottom reading). High blood pressure is said to be present if it is persistently at or above 140/90 mmHg.</p>