Blood pressure is the force that blood exerts against the walls of arteries as it flows through them. It is measured in millimetres of mercury (mmHg) and expressed as two numbers, systolic pressure (the top number) and diastolic pressure (the bottom number). Systolic pressure is the pressure in the arteries when the heart contracts and pumps blood out, while diastolic pressure is the pressure in the arteries when the heart is relaxed and filling with blood.
Blood pressure is regulated by a complex system of hormones, nerves, and physical factors, including the amount of blood in the body, the size and elasticity of the arteries, and the force of the heart’s contractions. Blood pressure can be affected by a variety of factors, including stress, physical activity, diet, and medications.
Blood Pressure Classifications
The blood pressure classifications used by healthcare professionals to diagnose and monitor high blood pressure (hypertension) are:
- Normal: A systolic blood pressure less than 120 mmHg and a diastolic blood pressure less than 80 mmHg.
- Elevated: A systolic blood pressure between 120-129 mmHg and a diastolic blood pressure less than 80 mmHg.
- Stage 1 hypertension: A systolic blood pressure between 130-139 mmHg or a diastolic blood pressure between 80-89 mmHg.
- Stage 2 hypertension: A systolic blood pressure of 140 mmHg or higher, or a diastolic blood pressure of 90 mmHg or higher.
- Hypertensive crisis: A systolic blood pressure of 180 mmHg or higher, or a diastolic blood pressure of 120 mmHg or higher. This is a medical emergency that requires immediate treatment to prevent serious complications.
It’s important to note that blood pressure can vary throughout the day and can be influenced by various factors such as stress, physical activity, and medication. Therefore, a diagnosis of hypertension is typically based on multiple blood pressure readings taken over a period of time, as well as other factors such as age, gender, and overall health status. Healthcare professionals will also take into account the presence of any other medical conditions or risk factors for cardiovascular disease when determining the appropriate blood pressure classification and treatment plan.
Monitoring and controlling blood pressure is an important aspect of maintaining overall health and preventing cardiovascular disease. Lifestyle changes, such as increasing physical activity, eating a healthy diet, and quitting smoking, can help lower blood pressure, as can medications prescribed by a healthcare professional.