English 15About Blood PressureWhat is Blood Pressure?Blood pressure is the force exerted by blood against the walls of the arteries.Systolic pressure occurs when the heart contracts. Diastolic pressure occurs whenthe heart expands. Blood pressure is measured in millimeters of mercury (mmHg).One's natural blood pressure is represented by the fundamental pressure, which ismeasured first thing in the morning while one is still at rest and before eating.What is Hypertension and How is it Controlled?Hypertension, which is abnormally high arterial blood pressure, if left unattended,can cause many health problems including stroke and heart attack. Hypertensioncan be controlled by altering one's lifestyle, avoiding stress, and with medicationunder a doctor’s supervision.To prevent hypertension or keep it under control:Do not smoke Exercise regularlyReduce salt and fat intake Have regular physical checkupsMaintain proper weightWhy Measure Blood Pressure at Home?Blood pressure measured at a clinic or doctor's office may cause worry orapprehension and can produce an elevated reading, 25 to 30 mmHg higher thanthat measured at home. Home measurement reduces the effects of outsideinfluences on blood pressure readings, supplements the doctor's readings andprovides a more accurate, complete blood pressure history.WHO Blood Pressure ClassificationStandards to assess high bloodpressure, without regard to age,have been established by theWorld Health Organization(WHO), as shown in the chart.Blood Pressure VariationsAn individual’s blood pressurevaries greatly on a daily andseasonal basis. It may vary by 30to 50 mmHg due to variousconditions during the day. In hypertensive individuals, variations are even morepronounced. Normally, the blood pressure rises while at work or play and falls toits lowest levels during sleep. So, do not be overly concerned by the results ofone measurement.Take measurements at the same time every day using the procedure describedin this manual to get to know your normal blood pressure.