High Blood Pressure Reading: What to Do Now

What your blood pressure numbers mean

Blood pressure has two numbers, measured in millimeters of mercury (mm Hg):

• Systolic (top): pressure in the arteries when the heart beats
• Diastolic (bottom): pressure between beats

If your two numbers fall in different categories, the higher category applies. A diagnosis of high blood pressure (hypertension) needs repeated readings over time, not a single measurement.

What to do after a high reading

1. Do not panic. Anxiety raises blood pressure further.
2. Sit quietly for 5 minutes in a chair with your back supported and feet flat on the floor.
3. Check your setup: empty your bladder first, no caffeine, exercise or smoking for 30 minutes, cuff on bare skin at heart level, arm resting on a table, no talking.
4. Use the right cuff size. A cuff too small for your arm can add 10 or more points.
5. Take two readings 1 minute apart and record both.
6. If it is still above 180/120, wait 5 minutes and check again. If it stays that high, call your doctor urgently. If you have any emergency symptoms, call 911 or your local emergency number.

Do not take extra doses of blood pressure medicine to bring a high reading down quickly unless your doctor has told you to. Rapid drops can be dangerous.

Why a reading can be high

Temporary rises

• pain, anxiety, anger or rushing
• white coat effect: readings are higher in the clinic than at home
• caffeine, nicotine, alcohol, and cannabis
• a full bladder
• cold
• talking or crossing your legs during the reading
• decongestants (pseudoephedrine, phenylephrine), NSAIDs such as ibuprofen, some migraine medicines, stimulants, steroids and some antidepressants

Ongoing high blood pressure

Most lasting high blood pressure is primary (essential) hypertension, linked to genes, age, weight, salt intake, inactivity and alcohol. About 1 in 10 cases has a specific cause, called secondary hypertension, which is more likely when blood pressure is very high, starts before age 30, or is hard to control:

• kidney disease and renal artery stenosis
• hyperaldosteronism (often with low potassium)
• obstructive sleep apnea
• thyroid disease
• pheochromocytoma, a rare tumor causing episodes of very high pressure with headache, sweating and palpitations
• preeclampsia in pregnancy

Symptoms of high blood pressure

High blood pressure is called a "silent" condition because it usually causes no symptoms, even at levels that damage the heart, brain and kidneys over years. Do not use how you feel to judge your blood pressure.

Our page on hypertension symptoms and whether you can feel high blood pressure covers which symptoms matter, which are myths, and the signs of long-term damage. The list below is what to watch for after a very high reading.

At very high levels, or when organs are under acute strain, symptoms can include:

• severe headache, often at the back of the head
• blurred vision, seeing spots, or vision loss
• chest pain or tightness
• shortness of breath
• confusion, drowsiness or seizures
• weakness or numbness of the face, arm or leg, or trouble speaking (stroke)
• nausea and vomiting
• nosebleeds, although these are rarely caused by blood pressure alone

Hypertensive urgency vs emergency

• Hypertensive urgency: very high pressure without new organ damage. It is usually managed by adjusting oral medicines over hours to days.
• Hypertensive emergency: very high pressure with organ damage such as heart attack, stroke, heart failure, aortic dissection, kidney injury or eclampsia. It needs hospital treatment with intravenous medicines, lowering the pressure carefully.

How high blood pressure affects the eyes

Long-standing high blood pressure narrows and damages the small blood vessels of the retina, called hypertensive retinopathy. Early stages cause no symptoms and are seen during an eye exam. Severe or sudden high pressure can cause bleeding, swelling of the optic nerve and blurred vision. High blood pressure also raises the risk of retinal vein and artery blockages and of stroke affecting vision.

Checking blood pressure at home

Home monitoring helps confirm a diagnosis and track treatment:

• Use a validated upper-arm cuff, not a wrist or finger device.
• Measure in the morning before medicines and in the evening, two readings each time, for 7 days before a doctor visit.
• Average the readings. A home average of 130/80 or more is considered high.
• Bring the monitor to your clinic once to check its accuracy.

Frequently asked questions

What is a dangerously high blood pressure reading?

A reading above 180/120 mm Hg is a hypertensive crisis. If it comes with chest pain, shortness of breath, back pain, severe headache, confusion, weakness, numbness or vision changes, call 911. If you have no symptoms, recheck after 5 minutes and contact your doctor promptly.

Can you feel high blood pressure?

Usually not. Most people with high blood pressure feel completely normal, which is why regular checks matter. Symptoms like headache, blurred vision or chest pain usually appear only at very high levels or when organs are affected.

Should I go to the ER for high blood pressure?

Go to the ER, or call 911, if a reading above 180/120 comes with symptoms such as chest pain, breathlessness, confusion, weakness, trouble speaking or vision loss. A high reading without symptoms usually needs a same-day call to your doctor rather than an ER visit.

What eye problems are caused by high blood pressure?

High blood pressure can damage the retina's blood vessels (hypertensive retinopathy), cause blockages of retinal veins or arteries, swell the optic nerve and contribute to stroke-related vision loss. Early damage has no symptoms and is found by an eye exam. Sudden blurred vision with very high pressure is an emergency.

How quickly can I lower my blood pressure?

Do not try to lower it rapidly at home. Sit and rest, breathe slowly and recheck. Long-term changes such as reducing salt, losing weight, regular exercise and limiting alcohol lower blood pressure over weeks. Medicines usually take 2 to 4 weeks to reach full effect.