What blood pressure is
Blood pressure is the force with which flowing blood pushes against the walls of the arteries. It is written as two numbers, for example 120/80 mmHg (millimetres of mercury). The higher number is the systolic pressure, measured when the heart contracts and pushes blood out. The lower number is the diastolic pressure, measured when the heart relaxes between beats.
Normal and abnormal readings
A healthy adult reading is around 120/80 mmHg. Two problems are important:
- High blood pressure (hypertension) means the arteries are under too much force for a long time. It often has no symptoms but raises the risk of heart attack, stroke and kidney damage.
- Low blood pressure (hypotension) can cause dizziness and fainting because organs receive too little blood.
Key idea
Blood pressure is measured with a sphygmomanometer, together with a stethoscope or a digital sensor. A cuff is wrapped around the upper arm, inflated to stop the blood flow, then slowly released while the two pressure values are read.
What affects blood pressure
Blood pressure rises with age, stress, a diet high in salt and fat, obesity, smoking and lack of exercise. In Malaysia, hypertension is common and is nicknamed a silent killer because many people do not know they have it. It can often be controlled with a healthier diet, regular exercise, less salt, and medicine when a doctor prescribes it.
Example
A clinic records a patient's blood pressure as 145/95 mmHg on several visits. Because both numbers are above the normal range, the doctor diagnoses hypertension and advises less salty food, more exercise and regular monitoring.
Remember
Sit and rest quietly before a reading, and keep the arm supported at heart level. One high reading is not enough to diagnose hypertension; several readings on different days are needed.