Blood pressure is a measure of the force exerted by the flow of blood on the walls of the arteries when the heart is pumping. This is of two types − systolic and diastolic. Systolic blood pressure occurs during a systole, or when the heart muscles are contracting and pumping blood. Diastolic blood pressure occurs during a diastole, or when the heart muscles are relaxing between beats.

Hypertension can occur without any symptoms, until it reaches a considerable level when symptoms appear. The normal range for blood pressure is 120/90 mmHg, where the upper reading is the systolic blood pressure and the lower one the diastolic blood pressure. During hypertension, blood pressure readings are higher than the established normal values. The systolic blood pressure usually needs to be over 140 mmHg for symptoms to occur. For this reason, one must regularly get their blood pressure checked. For accurate readings, the optimum placement of the monitor is on the right arm at the level of the heart. Also in cases of obese or underweight people, using the standard cuff size may result in possibly inaccurate readings.

While not applicable to all, researches have shown that many suffer from hypertension in a clinical environment, thus giving inaccurate readings, so one's home is usually the best place for measuring blood pressure.