High Blood Pressure: The Long-Term Condition That Rarely Announces Itself

High blood pressure usually causes no symptoms, but one raised reading does not establish hypertension. Accurate diagnosis uses repeated clinic readings and usually ambulatory or home monitoring before long term treatment decisions are made.

High blood pressure is a measured pattern Blood pressure is the pressure within the arteries as the heart pumps blood around the body. It is recorded in millimetres of mercury, written as mmHg. The systolic blood pressure is the higher number. It reflects arterial pressure while the heart contracts. The diastolic blood pressure is the lower number. It reflects arterial pressure while the heart relaxes between beats. Hypertension means that blood pressure remains above the diagnostic threshold. It is a pattern across suitable measurements, not simply one unusual reading. This lesson focuses on hypertension in non pregnant adults. Pregnancy uses a separate assessment and treatment pathway. Blood pressure naturally changes Blood pressure varies during the day and with activity, sleep, pain, stress, temperature, caffeine, medicines and measurement technique. A correct clinic measurement uses an appropriate cuff and suitable positioning. If the first reading is raised, NICE recommends repeating it during the consultation. For clinic readings between 140/90 and 180/120 mmHg, NICE recommends ambulatory blood pressure monitoring to confirm the diagnosis. Ambulatory blood pressure monitoring, called ABPM, uses a portable device that records repeated readings during normal daily life. Home blood pressure monitoring, called HBPM, is an alternative when ABPM is declined or cannot be tolerated. In most adults, hypertension is confirmed when the average waking ABPM or HBPM result is 135/85 mmHg or higher. These thresholds are diagnostic rules rather than boundaries between complete safety and certain harm. Cardiovascular risk changes gradually across blood pressure levels. Clinic and out of clinic readings can differ A white coat effect means that clinic readings are substantially higher than readings outside the clinical setting. Masked hypertension is the opposite pattern. Clinic readings appear acceptable, while ABPM or HBPM shows higher pressure during ordinary life. These patterns explain why one clinic reading can misclassify someone. They do not mean clinic measurements have no value. Clinicians also review earlier readings and whether medicines, illness or measurement problems could have affected the result. Hypertension has more than one cause Primary hypertension is the most common pattern in adults. It develops through interacting genetic, kidney, hormonal, vascular, nervous system, environmental and social influences. There is usually no single abnormality that fully explains primary hypertension. Ageing, higher salt intake, alcohol, inactivity and excess weight can contribute in some people. Secondary hypertension results from another condition or substance. Possible causes include kidney disease, hormonal disorders, obstructive sleep apnoea and selected medicines or drugs. Clinicians consider secondary hypertension when the age, severity, sudden onset, treatment response or other findings make it more likely. A risk factor changes probability. It does not prove why one person developed hypertension and should not be used to assign blame. Risk involves several organs and several pathways Sustained hypertension increases the workload on the heart and contributes to structural changes in arteries and small blood vessels. It can promote vascular remodelling, stiffness and endothelial dysfunction. These changes can interact with atherosclerosis and other cardiovascular risk factors. The relationship is more complex than pressure gradually wearing through a hosepipe. Hypertension can be both a cause and a consequence of kidney and vascular changes. Over time, hypertension increases the probability of stroke, coronary heart disease, heart failure, kidney disease, retinopathy and vascular dementia. These outcomes are possible rather than inevitable. Blood pressure is one contributor alongside cholesterol, diabetes, smoking, kidney disease, age and other factors. A heart attack or stroke is not always the first sign of hypertension. It is also not automatically caused by hypertension alone. Target organ damage changes the assessment Target organ damage means structural or functional change in organs associated with hypertension. It can involve the heart, brain, kidneys, eyes or blood vessels. Some target organ damage causes symptoms, while some is detected before the person notices anything. NICE recommends assessing cardiovascular risk and checking for target organ damage after hypertension is diagnosed or strongly suspected. Checks can include urine albumin:creatinine ratio, kidney blood tests, HbA1c, cholesterol, examination of the back of the eyes and an electrocardiogram. Each test answers a different question. One abnormal result does not prove that hypertension caused the change. Treatment decisions use more than the pressure number Lifestyle changes can lower blood pressure and provide wider health benefits. Relevant changes can include reducing salt, limiting excess alcohol, being active and stopping smoking. Medicine is offered for persistent stage 2 hypertension alongside lifestyle advice. Stage 2 includes an average ABPM or HBPM result of 150/95 mmHg or higher. For stage 1 hypertension, treatment decisions also consider age, cardiovascular risk, diabetes, kidney disease, established cardiovascular disease and target organ damage. Stage 1 includes an average ABPM or HBPM result from 135/85 to 149/94 mmHg. The clinician discusses likely benefits, adverse effects, treatment burden and the person's priorities. Frailty, multimorbidity and postural symptoms can change the safest target. Lowering sustained blood pressure reduces the risk of major cardiovascular events. It does not guarantee that every future event will be prevented. Management is not simply control instead of cure Primary hypertension often requires long term management, but its course can change. Weight change, reduced alcohol, lower salt intake and other interventions may lower pressure substantially. Treating a secondary cause can sometimes improve or resolve the hypertension. Some people still need ongoing medicine or monitoring afterwards. A reading within the target range does not prove that hypertension has disappeared. It may show that current treatment is working. Treatment should not be stopped or altered from one normal or low reading without clinical advice. Dizziness or fainting can indicate that the plan needs review. NICE recommends an annual review for adults with hypertension. The review covers blood pressure, lifestyle, symptoms, medicines and support. An incidental raised reading A 56 year old adult feels well during a routine medicine review. Their clinic blood pressure is 166/96 mmHg and remains raised when repeated correctly. The clinician does not confirm hypertension from those readings alone. They offer ABPM and assess cardiovascular risk and possible target organ damage. The average waking ABPM result is 152/96 mmHg. This confirms stage 2 hypertension under the current NICE pathway. The clinician also reviews kidney function, urine albumin, glucose, cholesterol, an electrocardiogram and the back of the eyes. The plan combines lifestyle support and antihypertensive medicine. The exact medicine and target depend on the person's health, safety factors and preferences. When urgent assessment is different A blood pressure reading of 180/120 mmHg or higher needs prompt clinical assessment rather than routine confirmation alone. NICE recommends same day specialist assessment when severe hypertension occurs with retinal bleeding, optic disc swelling or life threatening symptoms. Call 999 for persistent chest pain, new face drooping, arm weakness, speech difficulty, severe breathlessness, sudden confusion or collapse. A reading of 180/120 mmHg or higher without those symptoms still needs urgent advice from a GP or NHS 111. This lesson explains hypertension in adults. It cannot diagnose high blood pressure, set your target or determine whether you need treatment.

Hypertension is a persistent measurement pattern and a modifiable risk factor, not a symptom or inevitable injury process. Clinicians combine confirmed readings with cardiovascular risk, target organ assessment and personal circumstances.