Human blood pressure is the measured pressure in the wall of the arteries and recorded in millimeters of mercury. The measurement is written as a ratio to include two values: systolic and diastolic blood pressure.
Systolic and Diastolic
Systolic blood pressure measures the pressure in the arteries as the heart pumps blood. This represents the higher number, which is written first in blood pressure readings. Diastolic blood pressure measures the pressure in the arteries when the heart relaxes and fills with blood. It is written as the bottom number in the ratio.
Normal Levels
According to “Pharmacotherapy: A Pathophysiologic Approach,” the normal values for blood pressure are less than 120 for the systolic blood pressure and less than 80 for the diastolic blood pressure.
Measuring Blood Pressure
A physician measures blood pressure as part of a routine physical exam. An inflatable arm cuff attached to a pressure-measuring gauge is placed on the upper arm. If the blood pressure is high, the physician will take more readings before making a diagnosis of high blood pressure.
High Blood Pressure
Patients are considered to have high blood pressure when their values are above 140 for systolic blood pressure and above 90 for diastolic blood pressure. Patients require medications to keep blood pressure at normal level.
Risk Factors
As individuals age, the blood vessels lose flexibility and are unable to expand. A diet high in sodium may lead to water retention, which places more burden on the heart. A poor diet and lack of exercise may also lead to excess weight and obesity. Smoking and excess alcohol intake cause the blood pressure to increase.
References
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph T. Dipiro, Robert L. Talbert, et al.; 2008
- American Heart Association: Understanding Blood Pressure Readings
