Blood pressure reading is one of the most important vital signs, other than body temperature, pulse rate (heart rate), and respiratory rate. The heart works ceaselessly throughout our life, pumping blood at an average rate of 5 liters per minute. The heart, along with the blood circulatory system forms the supply system of the body, which provides nutrients and oxygen.
Actually, the functions of our blood circulatory system are too complex to be described in a sentence. Considering the important role it plays in our body, it is necessary that we observe the condition of our heart and the arterial network. This can be indirectly done, by checking the pressure. Yes, it is indeed possible to get a rough idea of how your heart is functioning, by simply measuring the pressure exerted by the blood, as it flows through the body.
How is Blood Pressure Measured
Blood pressure is measured using a smartly developed device called the Sphygmomanometer. It consists of an inflatable cuff, that is tied on the upper arm, at the level of the heart, for pressure measurement. In earlier days, the cuff was connected to a mercury manometer, which measured the pressure exerted by blood on the walls of the arteries. That is why, the pressure is traditionally measured in ‘mm Hg’, which is the pressure scale for mercury manometer. Nowadays, electronic meters are used, but the pressure reading is still calibrated in units of ‘mm Hg’.
The human heart is a pumping machine and it contracts to pump out blood and expands to take in blood. So, blood pressure has a periodic characteristic of rising and falling, with the contraction and relaxation. Hence, it has a maximum and minimum value. The maximum value is called ‘Systolic’ pressure and the minimum value is called ‘Diastolic’ pressure. So, it is always measured in pairs; a high value and a low value, which are the systolic and diastolic pressures respectively.
The blood pressure reading, that indicates normal functioning of an adult human heart, is not an absolute value. The reading that could be considered normal, varies from person to person. It also varies with age and medical history. In general, the concept of something being ‘normal’ is relative. However, it has been seen that a pressure of 112 mm Hg (Systolic) and 64 mm Hg (Diastolic) is considered normal, when the body is at rest. The normal values for children are lower than this.
The normal value of blood pressure varies with the time of the day, in an adult and also changes with the rate of activity. When in sleep or when resting, the systolic and diastolic values, both drop. While during strenuous activity, they increase. So the general range readings, that are considered normal, in an adult human being are 90-119 mm Hg (Systolic) and 60-79 mm Hg (Diastolic).
High Blood Pressure
Due to heart disease and blood circulation problems, sometimes, consistently high blood pressure (hypertension) is observed in some people. The initial range of values, which signify the onset of a heart disease (called pre-hypertension), are 120-139 mm Hg (Systolic) and 80-89 mm Hg (Diastolic). The range of pressure values, which are considered as the high blood pressure condition or stage 1 hypertension are 140-159 mm Hg (Systolic) and 90-99 mm Hg (Diastolic). The reading corresponding to stage 2 Hypertension is pressure in excess of 160 mm Hg (Systolic) and 100 mm Hg (Diastolic).
Low Blood Pressure
The condition opposite to hypertension, is low blood pressure. The lowering of pressure to below normal, indicates a weak heart condition. The range of readings, considered as low blood pressure or hypotension in adults, is any reading less than 90 mm Hg (Systolic) and 60 mm Hg (Diastolic).
These are the approximate blood pressure scale ranges, that indicate normal or abnormal functioning of the heart. If you have been diagnosed with a heart condition, it is a good idea to take regular blood pressure readings. That way, you can have a clear idea of your heart’s health and it may warn you of future problems, in advance.