Blood pressure measures the force exerted by circulating blood against the walls of the arteries. This measurement is expressed in millimeters of mercury (mmHg) using two numbers: systolic and diastolic pressure. The systolic reading (the higher number) represents the pressure when the heart beats and pushes blood through the arteries. The diastolic reading (the lower number) reflects the pressure in the arteries when the heart rests between beats.
Where 165 Falls on the Blood Pressure Scale
A systolic blood pressure reading of 165 mmHg is categorized as significantly elevated according to current medical guidelines. The American College of Cardiology and American Heart Association (ACC/AHA) define blood pressure categories to guide diagnosis and treatment. Normal blood pressure is considered less than 120 mmHg systolic and less than 80 mmHg diastolic.
Blood pressure categories progress from Elevated (120–129 mmHg systolic and less than 80 mmHg diastolic) to Stage 1 Hypertension (130–139 mmHg systolic or 80–89 mmHg diastolic). A systolic reading of 165 mmHg places a person firmly into the Stage 2 Hypertension category. This category begins at 140 mmHg systolic or 90 mmHg diastolic.
This classification indicates a serious elevation that warrants prompt medical intervention, including lifestyle changes and medication. For adults with an average blood pressure of 160 mmHg or greater systolic, prompt evaluation and drug treatment are recommended. If the pressure reaches 180 mmHg systolic or 120 mmHg diastolic, it is termed a Hypertensive Crisis, which is an emergency situation.
Why Sustained High Pressure is Dangerous
Sustained high blood pressure, particularly at 165 mmHg, causes progressive damage to arterial walls and vital organs. The constant, excessive force strains the heart muscle, causing the left ventricle to thicken and work harder. This strain can eventually lead to heart failure.
The elevated pressure damages the delicate inner lining of blood vessels, known as the endothelium. This damage encourages the buildup of plaque and promotes the stiffening of arteries, a process called atherosclerosis. Stiffened arteries increase the resistance the heart must pump against, creating a cycle of rising pressure and increasing damage.
Hypertension poses significant risks to the brain, increasing the likelihood of stroke (ischemic or hemorrhagic). The kidneys are also severely affected, as damaged small arteries impair their ability to regulate fluid and waste. This can result in chronic kidney disease and eventual kidney failure. Sustained hypertension can also damage the blood vessels supplying the eyes, known as retinopathy, leading to impaired vision or vision loss.
What to Do Immediately After a High Reading
If a single blood pressure reading is 165 mmHg systolic, the first step is to confirm the accuracy of the measurement. Use the correct technique by sitting quietly for five minutes, ensuring the arm is supported at heart level, and using a properly sized blood pressure cuff. Take multiple readings a few minutes apart and average the results to obtain a reliable number.
If the reading remains 165 mmHg or higher without severe symptoms, contact a healthcare provider immediately to schedule an urgent appointment within a few days. This serious elevation requires medical evaluation to determine the cause and initiate treatment, but it is not typically an emergency requiring an ambulance.
If a reading of 165 mmHg is accompanied by severe symptoms, this indicates a potential Hypertensive Emergency. These symptoms include severe headache, chest pain, shortness of breath, sudden vision changes, or difficulty speaking. Immediate emergency medical attention is necessary in this situation. While waiting for help, relaxing by lying down and practicing slow, deep breathing may help temporarily reduce pressure, as anxiety can contribute to temporary spikes.
Long-Term Strategies for Lowering Blood Pressure
Managing sustained high blood pressure requires combining lifestyle modifications with medical treatment. Dietary changes are highly effective, with the Dietary Approaches to Stop Hypertension (DASH) diet being the recommended strategy. This eating plan emphasizes fruits, vegetables, whole grains, and low-fat dairy while limiting saturated fat and sugar.
Reducing sodium intake is a powerful lifestyle change, ideally limiting consumption to 1,500 mg per day to notably lower blood pressure. Regular physical activity, such as aiming for at least 150 minutes of moderate-intensity aerobic exercise weekly, helps strengthen the heart and reduces strain on arteries. Modest weight loss can also lead to a substantial drop in blood pressure.
When lifestyle changes are insufficient to reach the target range, prescription medication becomes necessary. A healthcare provider may prescribe one or more classes of antihypertensive drugs, such as diuretics to reduce fluid, ACE inhibitors or ARBs to relax blood vessels, or calcium channel blockers to ease the heart’s workload. Consistent adherence to both the prescribed medication regimen and the recommended lifestyle changes offers the best chance for controlling blood pressure and preventing long-term health complications.