What should you know about high and low blood pressure?

Blood pressure is the force of blood moving through your arteries. A reading has an upper value, recorded as the heart pumps, and a lower value, recorded as the heart relaxes. High blood pressure means that pressure is repeatedly higher than the range considered healthy for you. It can place extra strain on blood vessels and organs over time, even when you feel well.

Low blood pressure means the pressure may be insufficient for your body at a particular time. Some people naturally have lower readings without problems. Others develop symptoms when blood flow to the brain briefly falls, particularly after standing, during illness, or when dehydrated. Light-headedness, blurred vision, weakness, nausea, or fainting can occur. A single reading can be affected by recent activity, stress, pain, caffeine, posture, or an incorrectly sized cuff, so context matters.

If you have a home monitor, sit quietly with your back supported and your feet on the floor before measuring. Keep your arm supported, use the cuff as directed, and record the reading, time, symptoms, and any relevant medicines. Do not stop or change prescribed blood-pressure treatment because of one result.

For repeated high readings, arrange a GP Consultation so the result can be checked and possible causes, medicines, and cardiovascular risks reviewed. For symptoms that suggest low blood pressure, rise slowly, drink fluids if you have not been told to restrict them, and sit or lie down when light-headed. A clinician may review hydration, bleeding, infection, heart rhythm, and medicines.

Seek urgent medical help for a blood-pressure concern accompanied by chest pain, severe breathlessness, new weakness or numbness on one side, trouble speaking, confusion, a severe sudden headache, or a faint that does not quickly resolve. Get prompt assessment after repeated fainting, an injury from a fall, black or bloody stools, or symptoms of serious dehydration. If you feel dizzy, avoid driving; Dizziness can have causes beyond blood pressure.

Ask what your readings mean in the context of your age, medicines, pregnancy status if relevant, and other health conditions. You can also ask whether you should monitor at home, how often to measure, whether a medicine could be contributing, and which symptoms should prompt same-day care.