Blood pressure is a measure of the force of blood against artery walls when the heart pumps. Pressure is measured in millimeters of mercury (mmHg) and is expressed as two numbers. For example, the optimal blood pressure for an adult is 120 over 80, or 120/80. The top number, called the systolic pressure, measures the highest pressure exerted when the heart contracts. The bottom number, called the diastolic pressure, shows the minimum pressure against the arteries when the heart rests between beats.
Blood pressure is measured with a cuff and stethoscope while the arm is in a resting position. The cuff is placed about an inch above the bend of the elbow and inflated until the mercury dial reaches 30 points higher than the person's usual systolic pressure, or 210 if no previous data is available. A stethoscope is placed into an artery on the inside of the elbow, and air is slowly released from the cuff. The point first heard with the pulse sound is the systolic pressure number; The point at which the sound disappears is the diastolic number.
Several factors can affect blood pressure, so a high reading doesn't necessarily mean a person has hypertension, or high blood pressure. Immediate stimuli such as fear, pain, anger, and some medications can temporarily raise a person's blood pressure. If a high reading has occurred, and one of these factors is present, then the person should be repeatedly monitored over a period of time to determine if this is a persistent condition, or if the reading was simply based on circumstances.
Hypertension is a leading cause of stroke, cardiovascular disorders, kidney, urologic, and neurologic diseases, and preeclampsia in pregnant women. A pressure reading of 120 over 80 or below is considered healthy. If the systolic number is above 120 to 139 or the diastolic number is above 80 to 89, a person is considered to have prehypertension. Systolic readings of 140 to 159 or diastolic readings of 90 to 99 are classified as stage 1 hypertension. Systolic measurements of 160 or more or diastolic measurements of 100 or more indicate the severe condition of stage 2 hypertension.
If a person has been determined to have hypertension, it is vital that the condition is addressed. Some lifestyle changes can help, such as eating healthy, maintaining a healthy weight, exercising regularly, and limiting salt and alcohol intake. In some cases, these efforts are not enough and medication is indicated. Even if a patient takes medication, healthy lifestyle changes will help manage the condition and can reduce the amount of medication needed to maintain a healthy blood pressure reading.
Sometimes patients have pressure readings lower than 90 over 60, which is considered the lower part of the normal range. This condition, called hypotension, can cause nothing more than a feeling of dizziness when moving quickly from a sitting position to a standing position. However, hypotension may be indicative of an underlying medical condition, such as heart failure, infection, severe diabetes, shock, gland disorders, or dehydration. Alcohol, anti-anxiety and antidepressants, diuretics, pain relievers, and some other medications can also cause hypotension. A person's blood pressure can change over time, so regular monitoring should be part of everyone's preventive health care.