Blood pressure represents the force exerted by circulating blood against the inner walls of your arteries. The heart, acting as a pump, generates this pressure to move blood into the extensive network of arteries, ensuring all organs and tissues receive what they need to function. This pressure fluctuates based on various activities, increasing during exertion and decreasing during rest.
Understanding Blood Pressure Measurement
A blood pressure reading consists of two numbers. The top number, systolic pressure, measures the force in your arteries when your heart contracts and pushes blood out. The bottom number, diastolic pressure, reflects the pressure in your arteries when your heart relaxes between beats and refills with blood. These measurements are expressed in millimeters of mercury (mmHg), for example, 120/80 mmHg.
Blood pressure is measured using a sphygmomanometer, an inflatable cuff wrapped around the upper arm. This cuff temporarily restricts blood flow and then slowly deflates, allowing the device to detect pressures during heartbeats and relaxation periods. Accurate measurement requires a calm environment, with the individual seated quietly, feet flat on the floor, and the arm supported at heart level. Avoiding caffeine, exercise, and smoking for at least 30 minutes before a reading helps ensure reliable results.
Healthy and Abnormal Blood Pressure Levels
For most adults, a healthy blood pressure reading is below 120/80 mmHg. Blood pressure can vary naturally throughout the day due to activity, age, and other factors.
Readings that fall outside this range are categorized to indicate potential health concerns. Elevated blood pressure occurs when the systolic reading is between 120 and 129 mmHg and the diastolic reading remains below 80 mmHg. Hypertension is classified into stages: Stage 1 hypertension is indicated by a systolic pressure between 130 and 139 mmHg or a diastolic pressure between 80 and 89 mmHg. Stage 2 hypertension is diagnosed when the systolic pressure is 140 mmHg or higher, or the diastolic pressure is 90 mmHg or higher.
A hypertensive crisis, a medical emergency, is defined by a systolic reading of 180 mmHg or higher and/or a diastolic reading of 120 mmHg or higher. Conversely, hypotension is defined as readings below 90/60 mmHg.
Hypertension Causes and Health Impacts
Hypertension develops when the force of blood against artery walls is consistently elevated, making the heart work harder to pump blood. This condition often progresses over several years without noticeable symptoms, which is why it is sometimes referred to as a “silent condition.” Factors contributing to its development include genetics, increasing age, and ethnicity; for instance, individuals of Black African, Black Caribbean, or South Asian descent have a higher risk.
Lifestyle choices influence blood pressure levels. An unhealthy diet, particularly one high in sodium and saturated fats, contributes to hypertension. Lack of regular physical activity and obesity also increase the risk, as excess weight places additional strain on the cardiovascular system. High alcohol consumption and chronic stress also contribute to elevated blood pressure. Underlying medical conditions such as kidney disease, diabetes, and sleep apnea can also lead to hypertension.
Untreated hypertension can quietly damage blood vessels and organs over time, leading to severe health complications. The constant high pressure can stiffen and narrow arteries, limiting blood flow and oxygen supply to vital tissues. This damage increases the risk of coronary artery disease, which can result in chest pain (angina), irregular heart rhythms (arrhythmias), or a heart attack. The heart muscle may weaken or enlarge due to the increased workload, potentially leading to heart failure. Hypertension also raises the risk of stroke, a condition where blood flow to the brain is interrupted, and can contribute to vascular dementia, kidney disease, and vision loss.
Hypotension Causes and Health Impacts
Hypotension occurs when the circulating blood pressure is lower than normal. While often less severe than hypertension, a significant or sustained drop in blood pressure can be serious because it may lead to insufficient oxygen delivery to the body’s tissues. Readings below 90/60 mmHg are low.
Common causes of hypotension include dehydration, which reduces overall blood volume, and certain medications, especially those used to treat high blood pressure or heart conditions. Heart conditions such as abnormal heart rhythms or heart failure also cause hypotension. Endocrine problems, severe infections like sepsis, and significant blood loss from injuries or internal bleeding are other causes. Sudden changes in body position, such as standing up quickly, can cause a temporary drop in blood pressure known as orthostatic hypotension.
Symptoms of hypotension often include feeling light-headed, dizzy, or unsteady, particularly when changing positions. Individuals may also experience blurred vision, fatigue, headache, confusion, or nausea. In more severe cases, a sudden drop in blood pressure can lead to fainting or even shock, a life-threatening condition where organs do not receive enough blood flow. While some people live with consistently low blood pressure without symptoms, any sudden or symptomatic drop warrants medical attention to identify and address the underlying cause.
Managing Blood Pressure Through Lifestyle
Adopting lifestyle modifications contributes to maintaining healthy blood pressure levels and managing existing conditions. Achieving and maintaining a healthy weight is important, as even modest weight loss can lead to a reduction in blood pressure. For instance, losing approximately 2.2 pounds (1 kilogram) can lower blood pressure by about 1 mmHg.
Regular physical activity is important. Aiming for at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking, jogging, cycling, or swimming, can lower blood pressure by 5 to 8 mmHg. Incorporating a healthy diet, like the Dietary Approaches to Stop Hypertension (DASH) eating plan, which emphasizes fruits, vegetables, and low-fat dairy while reducing saturated fat, can lower blood pressure by up to 11 mmHg. Reducing sodium intake to less than 2,300 mg per day, or ideally 1,500 mg for most adults, can also reduce blood pressure by 5 to 6 mmHg.
Limiting alcohol consumption to no more than two drinks per day for men and one drink per day for women can reduce blood pressure by about 4 mmHg. Quitting smoking also helps, as smoking damages blood vessels and increases blood pressure risk. Effective stress management techniques, such as mindfulness or deep breathing, and ensuring adequate, restorative sleep, also help control blood pressure. Consistent home blood pressure monitoring and regular check-ups with healthcare professionals are important for personalized advice and treatment adjustments.