More than 120 over 80 and less than 140 over 90 (120/80-140/90): You have a normal blood pressure reading but it is a little higher than it should be, and you should try to lower it. Make healthy changes to your lifestyle.
What blood pressure readings mean
As you can see from the blood pressure chart, only one of the numbers has to be higher or lower than it should be to count as either high blood pressure or low blood pressure:
90 over 60 (90/60) or less: You may have low blood pressure. More on low blood pressure.
More than 90 over 60 (90/60) and less than 120 over 80 (120/80): Your blood pressure reading is ideal and healthy. Follow a healthy lifestyle to keep it at this level.
More than 120 over 80 and less than 140 over 90 (120/80-140/90): You have a normal blood pressure reading but it is a little higher than it should be, and you should try to lower it. Make healthy changes to your lifestyle.
140 over 90 (140/90) or higher (over a number of weeks): You may have high blood pressure (hypertension). Change your lifestyle - see your doctor or nurse and take any medicines they may give you. More on high blood pressure
So:
if your top number is 140 or more - then you may have high blood pressure, regardless of your bottom number.
if your bottom number is 90 or more - then you may have high blood pressure, regardless your top number.
if your top number is 90 or less - then you may have low blood pressure, regardless of your bottom number.
if your bottom number is 60 or less - then you may have low blood pressure, regardless of your top number.
If your blood pressure is extremely high, there may be certain symptoms to look out for, including:
One of the most dangerous aspects of hypertension is that you may not know that you have it. In fact, nearly one-third of people who have high blood pressure don't know it. The only way to know if your blood pressure is high is through regular checkups. This is especially important if you have a close relative who has high blood pressure.
If your blood pressure is extremely high, there may be certain symptoms to look out for, including:
• Severe headache.
• Fatigue or confusion.
• Vision problems.
• Chest pain.
• Difficulty breathing.
• Irregular heartbeat.
• Blood in the urine.
• Pounding in your chest, neck, or ears.
What are the Symptoms of High Blood Pressure?
Looking for a list of symptoms?
If you are looking for a list of symptoms and signs of high blood pressure (HBP or hypertension), you won’t find them here. This is because most of the time, there are none.
Myth: People with high blood pressure will experience symptoms, like nervousness, sweating, difficulty sleeping or facial flushing.
Truth: High blood pressure is a largely symptomless “silent killer.” If you ignore your blood pressure because you think a certain symptom or sign will alert you to the problem, you are taking a dangerous chance with your life.
• DO NOT attempt to diagnose yourself. Clinical diagnosis should only be made by a healthcare professional.
• Know your blood pressure numbers and make changes that matter to protect your health.
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In most cases, high blood pressure does not cause headaches or nosebleeds
• The best evidence indicates that high blood pressure does not cause headaches or nosebleeds, except in the case of hypertensive crisis, a medical emergency when blood pressure is 180/120 mm Hg or higher. If your blood pressure is unusually high AND you have headache or nosebleed and are feeling unwell, wait five minutes and retest. If your reading remains at 180/120 mm Hg or higher, call 9-1-1.
• If you are experiencing severe headaches or nosebleeds and are otherwise unwell, contact your doctor as they could be symptoms of other health conditions.
Other inconclusively related symptoms
A variety of symptoms may be indirectly related to, but are not always caused by, high blood pressure, such as:
• Blood spots in the eyes
Blood spots in the eyes (subconjunctival hemorrhage) are more common in people with diabetes or high blood pressure, but neither condition causes the blood spots. Floaters in the eyes are also not related to high blood pressure. However, an eye doctor (ophthalmologist) may be able to detect damage to the optic nervecaused by untreated high blood pressure.
• Facial flushing
Facial flushing occurs when blood vessels in the face dilate. It can occur unpredictably or in response to certain triggers such as sun exposure, cold weather, spicy foods, wind, hot drinks and skin-care products. Facial flushing can also occur with emotional stress, exposure to heat or hot water, alcohol consumption and exercise — all of which can raise blood pressure temporarily. While facial flushing may occur while your blood pressure is higher than usual, high blood pressure is not the cause of facial flushing.
• Dizziness
While dizziness can be a side effect of some blood pressure medications, it is not caused by high blood pressure. However, dizziness should not be ignored, especially if the onset is sudden. Sudden dizziness, loss of balance or coordination and trouble walking are all warning signs of a stroke. High blood pressure is a leading risk factor for stroke.
Low blood pressure (hypotension)
Low blood pressure might seem desirable, and for some people, it causes no problems. However, for many people, abnormally low blood pressure (hypotension) can cause dizziness and fainting. In severe cases, low blood pressure can be life-threatening.
A blood pressure reading lower than 90 millimeters of mercury (mm Hg) for the top number (systolic) or 60 mm Hg for the bottom number (diastolic) is generally considered low blood pressure.
The causes of low blood pressure can range from dehydration to serious medical or surgical disorders. It's important to find out what's causing your low blood pressure so that it can be treated.
Symptoms
For some people, low blood pressure signals an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:
• Dizziness or lightheadedness
• Fainting (syncope)
• Blurred vision
• Nausea
• Fatigue
• Lack of concentration
Shock
Extreme hypotension can result in this life-threatening condition. Signs and symptoms include:
• Confusion, especially in older people
• Cold, clammy, pale skin
• Rapid, shallow breathing
• Weak and rapid pulse
When to see a doctor
If you have indications of shock, seek emergency medical help.
If you have consistently low blood pressure readings but feel fine, your doctor is likely just to monitor you during routine exams.
Even occasional dizziness or lightheadedness may be a relatively minor problem — the result of mild dehydration from too much time in the sun or a hot tub, for example. Still, it's important to see your doctor if you have signs or symptoms of hypotension because they can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you're doing at the time.
Causes
Blood pressure is a measurement of the pressure in your arteries during the active and resting phases of each heartbeat.
• Systolic pressure. The top number in a blood pressure reading is the amount of pressure your heart generates when pumping blood through your arteries to the rest of your body.
• Diastolic pressure. The bottom number in a blood pressure reading refers to the amount of pressure in your arteries when your heart is at rest between beats.
Current guidelines identify normal blood pressure as lower than 120/80 mm Hg.
Throughout the day, blood pressure varies, depending on body position, breathing rhythm, stress level, physical condition, medications you take, what you eat and drink, and time of day. Blood pressure is usually lowest at night and rises sharply on waking.
Blood pressure: How low can you go?
What's considered low blood pressure for you may be normal for someone else. Most doctors consider blood pressure too low only if it causes symptoms.
Some experts define low blood pressure as readings lower than 90 mm Hg systolic or 60 mm Hg diastolic. If either number is below that, your pressure is lower than normal.
A sudden fall in blood pressure can be dangerous. A change of just 20 mm Hg — a drop from 110 systolic to 90 mm Hg systolic, for example — can cause dizziness and fainting when the brain fails to receive an adequate supply of blood. And big plunges, such as those caused by uncontrolled bleeding, severe infections or allergic reactions, can be life-threatening.
Conditions that can cause low blood pressure
Medical conditions that can cause low blood pressure include:
• Pregnancy. Because the circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. This is normal, and blood pressure usually returns to your pre-pregnancy level after you've given birth.
• Heart problems. Some heart conditions that can lead to low blood pressure include extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure.
• Endocrine problems. Thyroid conditions such as parathyroid disease, adrenal insufficiency (Addison's disease), low blood sugar (hypoglycemia) and, in some cases, diabetes can trigger low blood pressure.
• Dehydration. When your body loses more water than it takes in, it can cause weakness, dizziness and fatigue. Fever, vomiting, severe diarrhea, overuse of diuretics and strenuous exercise can lead to dehydration.
• Blood loss. Losing a lot of blood, such as from a major injury or internal bleeding, reduces the amount of blood in your body, leading to a severe drop in blood pressure.
• Severe infection (septicemia). When an infection in the body enters the bloodstream, it can lead to a life-threatening drop in blood pressure called septic shock.
• Severe allergic reaction (anaphylaxis). Common triggers of this severe and potentially life-threatening reaction include foods, certain medications, insect venoms and latex. Anaphylaxis can cause breathing problems, hives, itching, a swollen throat and a dangerous drop in blood pressure.
• Lack of nutrients in your diet. A lack of the vitamins B-12 and folate can keep your body from producing enough red blood cells (anemia), causing low blood pressure.
Medications that can cause low blood pressure
Some medications can cause low blood pressure, including:
• Water pills (diuretics), such as furosemide (Lasix) and hydrochlorothiazide (Maxzide, Microzide, others)
• Alpha blockers, such as prazosin (Minipress)
• Beta blockers, such as atenolol (Tenormin) and propranolol (Inderal, Innopran XL, others)
• Drugs for Parkinson's disease, such as pramipexole (Mirapex) or those containing levodopa
• Certain types of antidepressants (tricyclic antidepressants), including doxepin (Silenor) and imipramine (Tofranil)
• Drugs for erectile dysfunction, including sildenafil (Revatio, Viagra) or tadalafil (Adcirca, Cialis), particularly when taken with the heart medication nitroglycerin
Types of low blood pressure
Doctors often break down low blood pressure (hypotension) into categories, depending on the causes and other factors. Some types of low blood pressure include:
• Low blood pressure on standing up (orthostatic, or postural, hypotension).This is a sudden drop in blood pressure when you stand up from a sitting position or after lying down.
Gravity causes blood to pool in your legs when you stand. Ordinarily, your body compensates by increasing your heart rate and constricting blood vessels, thereby ensuring that enough blood returns to your brain.
But in people with orthostatic hypotension, this compensating mechanism fails and blood pressure falls, leading to dizziness, lightheadedness, blurred vision and even fainting.
Orthostatic hypotension can occur for various reasons, including dehydration, prolonged bed rest, pregnancy, diabetes, heart problems, burns, excessive heat, large varicose veins and certain neurological disorders.
A number of medications also can cause orthostatic hypotension, particularly drugs used to treat high blood pressure — diuretics, beta blockers, calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors — as well as antidepressants and drugs used to treat Parkinson's disease and erectile dysfunction.
Orthostatic hypotension is especially common in older adults, but it also affects young, otherwise healthy people who stand up suddenly after sitting with their legs crossed for long periods or after squatting for a time.
It's also possible to have delayed orthostatic hypotension, with signs and symptoms developing 5 to 10 minutes after a change in posture. This might be a milder form of the condition, or it could be an early stage of it.
• Low blood pressure after eating (postprandial hypotension). This sudden drop in blood pressure after eating affects mostly older adults.
Blood flows to your digestive tract after you eat. Ordinarily, your body increases your heart rate and constricts certain blood vessels to help maintain normal blood pressure. But in some people these mechanisms fail, leading to dizziness, faintness and falls.
Postprandial hypotension is more likely to affect people with high blood pressure or autonomic nervous system disorders such as Parkinson's disease.
Lowering the dose of blood pressure drugs and eating small, low-carbohydrate meals might help reduce symptoms.
• Low blood pressure from faulty brain signals (neurally mediated hypotension). This disorder, which causes a blood pressure drop after standing for long periods, mostly affects young adults and children. It seems to occur because of a miscommunication between the heart and the brain.
• Low blood pressure due to nervous system damage (multiple system atrophy with orthostatic hypotension). Also called Shy-Drager syndrome, this rare disorder causes progressive damage to the autonomic nervous system, which controls involuntary functions such as blood pressure, heart rate, breathing and digestion. It's associated with having very high blood pressure while lying down.
Risk factors
Low blood pressure (hypotension) can occur in anyone, though certain types of low blood pressure are more common depending on your age or other factors:
• Age. Drops in blood pressure on standing or after eating occur primarily in adults older than 65. Neurally mediated hypotension primarily affects children and younger adults.
• Medications. People who take certain medications, for example, high blood pressure medications such as alpha blockers, have a greater risk of low blood pressure.
• Certain diseases. Parkinson's disease, diabetes and some heart conditions put you at a greater risk of developing low blood pressure.
Complications
Even moderate forms of low blood pressure can cause dizziness, weakness, fainting and a risk of injury from falls.
And severely low blood pressure can deprive your body of enough oxygen to carry out its normal functions, leading to damage to your heart and brain.
