When To Call Your Doctor
The risks of both high and low blood pressure make monitoring your blood pressure at home essential to your overall health and well-being. Both Dr. Wong and Dr. Desai recommend calling your healthcare provider if your self-monitored blood pressure readings are greater than 180/120 mmHgeven if you have no other symptoms.
You should call 911 if these blood pressure readings are associated with symptoms of organ damage, such as headache, vision changes, weakness, numbness, chest pain or shortness of breath, says Dr. Wong.
If You Notice A Sudden Decline In Blood Pressure
A single lower-than-normal reading is not cause for alarm, unless you are experiencing any other symptoms or problems. If you experience any dizziness, lightheadedness, nausea or other symptoms, its a good idea to consult with your healthcare provider. To help with your diagnosis, keep a record of your symptoms and activities at the time they occurred.
Is low blood pressure related to low heart rate? Find out.
Written by American Heart Association editorial staff and reviewed by science and medicine advisers. See our editorial policies and staff.
Last Reviewed: Oct 31, 2016
Blood Pressure: How Low Is Too Low
We all know that high blood pressure is bad for us. But what about low blood pressure?
The question is important because of new blood pressure guidelines.
They say hypertension should be treated in most adults when the systolic is greater than 130. The old recommendations were 140.
A new study has found that some people may be doing themselves more harm than good by lowering their BP too much. They could be setting themselves up for a trip to the emergency room or worse.
Researchers from Kaiser Permanente in California wanted to find out if lowering blood pressure could cause unintended health problems.1
They reviewed the health records of more than 475,000 patients who were on blood pressure medication. The patients mean age was 65.2
During the one-year study period, the researchers noted when a patients systolic blood pressure had dropped below 110 mmHg.
Patients whose blood pressure fell this low had a 50% greater risk of serious falls and fainting.
About 40 million Americans are taking high blood pressure medication.3
The study indicates that almost 12 million of them could be putting themselves at risk of falling or fainting by lowering their blood pressure too much.
Falls are the leading cause of accidental death in people over 65.4 They are also the most common cause of emergency room admissions.
Dr. John Sim is a nephrologist with Kaiser Permanente Los Angeles Medical Center. He was the studys lead author.
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Diastolic Blood Pressure: How Low Is Too Low
- May 17, 2015
Blood pressure consists of two numbers. Systolic pressure, the force exerted on blood vessels when the heart beats, is the upper number. Diastolic pressure, the force exerted when the heart is at rest, is on the bottom in more ways than one. Systolic pressure attracts the lions share of attention from physicians and patients, says UAB cardiologist Jason Guichard, M.D., Ph.D.
Physicians are busy people, and like it or not they often focus on a single number, Guichard said. Systolic blood pressure is the focus, and diastolic pressure is almost completely ignored. That is a mistake, he argues. The majority of your arteries feed your organs during systole. But your coronary arteries are different they are surrounding the aortic valve, so they get blood only when the aortic valve closes and that happens in diastole.
Diastolic pressure has been getting more attention lately, however, thanks in part to an influential paper in Hypertension, written in 2011 by Guichard and Ali Ahmed, M.D., then a professor of medicine in UABs Division of Gerontology, Geriatrics and Palliative Care and now the associate chief of staff for Health and Aging at the Veterans Affairs Medical Center in Washington, D.C.
Most people are trying to lower their blood pressure. What would you define as too low, and why is that a problem?
New Findings Focus On Diastolic Blood Pressurethe Second Number In Your Blood Pressure Reading
Image: mangostock/Thinkstock
Of the two numbers that make up your blood pressure reading, the first one typically gets more attention. That’s because as people age, their arteries lose their elasticity, and the inner walls are more likely to accumulate cholesterol-laden plaque. These factors tend to raise systolic blood pressure, a measure of the pressure inside the arteries when the heart contracts to pump blood throughout the body.
Current guidelines suggest that most people should aim for a systolic blood pressure reading of 140 millimeters of mercury or lower. But last year, a widely publicized clinical trial suggested that a target of 120 mm Hg could further reduce the dangers associated with high blood pressure .
Yet reaching that lower target required an average of three blood pressure medications, which resulted in more side effects. Now, two recent observational studies highlight some concerns about blood pressure that’s too low, particularly with regard to diastolic blood pressure. Diastolic blood pressure represents the pressure between beats when the heart relaxes.
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What Is Low Blood Pressure
Hypotension is the medical term for low blood pressure .
A blood pressure reading appears as two numbers. The first and higher of the two is a measure of systolic pressure, or the pressure in the arteries when the heart beats and fills them with blood. The second number measures diastolic pressure, or the pressure in the arteries when the heart rests between beats.
Optimal blood pressure is less than 120/80 . In healthy people, low blood pressure without any symptoms is not usually a concern and does not need to be treated. But low blood pressure can be a sign of an underlying problem — especially in the elderly — where it may cause inadequate blood flow to the heart, brain, and other vital organs.
Chronic low blood pressure with no symptoms is almost never serious. But health problems can occur when blood pressure drops suddenly and the brain is deprived of an adequate blood supply. This can lead to dizziness or lightheadedness. Sudden drops in blood pressure most commonly occur in someone who’s rising from a lying down or sitting position to standing. This kind of low blood pressure is known as postural hypotension or orthostatic hypotension. Another type of low blood pressure can occur when someone stands for a long period of time. This is called neurally mediated hypotension.
How Does Blood Pressure Work
During relaxation of the heart , the left ventricle of the heart fills with blood returning from the lungs. The left ventricle then contracts and pumps blood into the arteries . The blood pressure in the arteries during contraction of the ventricle is higher because blood is being actively ejected into the arteries. It is lower during relaxation of the ventricle when no blood is being ejected into the arteries. The pulse we feel when we place our fingers over an artery is caused by the contraction of the left ventricle and the ejection of blood.
Blood pressure is determined by two factors:
Generally, blood pressure tends to be higher if more blood is pumped into the arteries or if the arterioles are narrow and/or stiff. Narrow and/or stiff arterioles, by resisting the flow of blood, increase blood pressure. Arterioles may become narrower when the muscles surrounding them contract. Arterioles may become stiff and narrow when older patients develop atherosclerosis.
Blood pressure tends to be lower if less blood is being pumped into the arteries or if the arterioles are larger and more flexible and, therefore, have less resistance to the flow of blood.
The heart rate increases and the forcefulness of the heart’s contractions increase, pumping more blood through the heart.
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How Is Blood Pressure Determined
Several factors influence blood pressure. Blood volume and blood vessel wall behavior are two important determinants of blood pressure. The more blood pumped with each heartbeat, the higher the blood pressure. The presence of stiff or narrow artery walls that resist blood flow also increases blood pressure. Having lower blood volume and open, flexible arteries decreases blood pressure.
What Is Blood Pressure
As blood pumps through the circulatory system, it pushes against the walls of the arteries and veins. Blood pressure is the force of the blood as it presses against the blood vessel walls. It is measured in systolic pressure and diastolic pressure .
Blood pressure rises and falls throughout the day. Normal blood pressure is considered to be below 120/80 mm Hg. In a blood pressure reading, the top number refers to systolic pressure, and the bottom number refers to the diastolic pressure.
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About Low Blood Pressure
The heart pumps a constant supply of blood around the body. The blood flows through different networks in the body, for example, arteries, veins and capillaries. Blood pressure is a measure of the force of the blood on the walls of the arteries as the blood flows through them.
It’s measured in millimetres of mercury and recorded as two measurements:
- systolic pressure the pressure when your heart beats and squeezes blood into your arteries
- diastolic pressure the pressure when your heart rests between beats
For example, if your systolic blood pressure is 120mmHg and your diastolic blood pressure is 80mmHg, your blood pressure is 120 over 80, which is commonly written as 120/80.
Normal blood pressure is between 90/60 and 140/90. If you have a sustained reading of 140/90 or more, you have high blood pressure . This puts you at greater risk of developing serious health conditions, such as heart attack or stroke.
People with a blood pressure reading under 90/60 are usually regarded as having low blood pressure.
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Symptoms Of Low Blood Pressure In Elderly Individuals
As long as you feel OK, a low blood pressure reading is generally nothing to worry about. Doctors are not usually concerned about a low BP in otherwise healthy individuals.
So, when is blood pressure too low? You should see your healthcare provider if you experience hypotension symptoms such as:
- Dizziness
- Confusion or inability to concentrate
- Nausea
- An irregular or rapid heartbeat
- Weakness
What Causes Low Blood Pressure
The cause of low blood pressure isn’t always clear. It may be associated with the following:
- Pregnancy
- Some prescription medicines such as for high blood pressure, depression or Parkinsonâs disease
- Heart failure
- Heart arrhythmias
- Widening, or dilation, of the blood vessels
- Severe dehydration from vomiting, diarrhea, or fever
- A reaction to medication or alcohol
- A severe allergic reaction called anaphylaxis that causes an irregular heartbeat
Who Gets Postural Hypotension?
Postural hypotension, which is low blood pressure when standing up suddenly, can happen to anyone for a variety of reasons, such as dehydration, lack of food, or being overly fatigued. It can also be influenced by genetic make-up, aging, medication, dietary and psychological factors, and acute triggers, such as infection and allergy.
Postural hypotension occurs most frequently in people who are taking drugs to control high blood pressure . It can also be related to pregnancy, strong emotions, hardening of the arteries , or diabetes. The elderly are particularly affected, especially those who have high blood pressure or autonomic nervous system dysfunction.
Hypotension after meals is a common cause of dizziness and falls after eating. This is most common after large meals containing a lot of carbohydrates. Itâs believed to be caused by blood pooling into the vessels of the stomach and intestines.
Common causes of naturally occurring postural hypotension include:
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When Does Low Blood Pressure Become Dangerous
The big concern with being dizzy, feeling faint, or having blurred vision due to low blood pressure is that you could fall.
Fracture your hip or spine, and you wont be able to move around easily or enjoy your independenceand that can harm your quality of life. If you experience lightheadedness, dizziness, or any of the symptoms above, sit down right away. Then bring your feet above heart level.
Its all about gravity, Dr. Mehta explains. When youre standing, your head is on top, and the blood pools down to the legs. Elevating your legs brings the blood back to your core and brain.
While youre resting, ask someone to bring you a glass of water, in case dehydration was the reason your blood pressure dropped.
After you feel better, contact your physicians office, and let them know what happened, Dr. Mehta says.
Important: Sometimes very low blood pressure can lead to shock, which means your body isnt getting enough oxygen and nutrients to work properly. The symptoms of shock include:
If you have any of these symptoms, call 911 right away. Shock can be life-threatening.
Postural Or Orthostatic Hypotension
Postural or orthostatic hypotension occurs when your blood pressure falls after a sudden movement. For example, you may feel dizzy or faint after changing posture, such as sitting up from a lying position, or standing up from a sitting position. This may cause you to lose your balance and fall over. You may also feel light-headed, have blurred vision, or lose consciousness.
The symptoms of postural or orthostatic hypotension should only last a few minutes as your blood pressure adjusts to your new position. This type of low blood pressure tends to affect people more as they get older when it can lead to more frequent falls. Similar symptoms may also occur after exercise.
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When To See Your Gp
You should see your GP if you have frequent symptoms of low blood pressure. Your GP can measure your blood pressure and help identify any underlying causes of the problem.
All adults should have their blood pressure checked at least every five years. If you haven’t had yours measured or don’t know what your reading is, ask your practice nurse or GP to check it.
Try Lifestyle Changes First
There are a number of measuresincluding losing weight, exercising more, cutting back on sodium, and drinking less alcoholthat can sometimes reduce or even eliminate your need for drugs. If your systolic level is moderately elevated , consider drugs only if after six months of serious attempts at diet and lifestyle changes your blood pressure hasnt dropped enough.
If youre 60 or older or you have diabetes or kidney disease and already take blood pressure medications that arent causing side effects, theres no need to change your prescription. But if the effects are bothersome and your levels are under control, ask your doctor about switching your prescription, lowering your dose, or cutting back to one drug.
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What Are The Signs And Symptoms Of Low Blood Pressure
The symptoms of low blood pressure may include:
- light-headedness
- fainting
These symptoms can occur when doing nothing. They are more likely to occur when changing position, such as standing up or when straining on the toilet.
However, often there are no symptoms and low blood pressure is often only identified as a result of a routine medical examination or during the course of an investigation for some other condition or underling illness.
Low blood pressure may be more serious in elderly people who may have an underlying illness or who may be at risk of a fall.
Check your symptoms with healthdirects Symptom Checker to get advice on when to seek medical attention.
Improving Health With Current Research
Learn about the following ways the NHLBI continues to translate current research into improved health for people with abnormally low blood pressure. Research on this topic is part of the NHLBIs broader commitment to advancing heart and vascular disease scientific discovery.
- Testing Treatments for Cardiac Arrest and Trauma. The Resuscitation Outcomes Consortium clinical trial network tested treatments to address high morbidity and mortality rates from out-of-hospital cardiac arrest and severe traumatic injury. ROC investigators compared different strategies for supplemental fluids in trauma patients who have low blood pressure. Other ROC studies found a link between low blood pressure readings and the need for emergency procedures.
- Understanding How Low Blood Pressure Affects Diverse Populations. NHLBI-supported researchers are studying low blood pressure in different populations. Investigators in the NHLBIs Atherosclerosis Risk in Communities Study found that people who have low blood pressure when standing up, known as orthostatic hypotension, are at higher risk for stroke. In a follow-up study of NHLBIs Honolulu Heart Program, researchers found older Japanese men who had orthostatic hypotension were nearly twice as likely to die within the next four years as those who did not have orthostatic hypotension. NHLBIs Cardiovascular Health Study found that orthostatic hypotension was common in older adults, increases with age, and is linked to cardiovascular diseases.
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When Is Low Blood Pressure An Emergency
In many cases, low blood pressure readings are not a cause for concern. A person with low blood pressure may not even be aware that their blood pressure is low, as it does not cause symptoms in many cases.
There is also no specific cutoff point at which blood pressure becomes too low or dangerously low, as it may vary from person to person.
Some people may have chronic low blood pressure and can be otherwise healthy. The American Heart Association note that most doctors will only consider chronic low blood pressure to be dangerous if it causes other symptoms.
Severe symptoms that come on suddenly may also be a cause for concern.
While symptoms may vary from person to person, they typically include:
If a person experiences any of these symptoms, they should contact a doctor.
When blood pressure is very low or drops rapidly, it can also be a medical emergency. The note that extremely low drops in blood pressure may put the bodys organs at risk of not getting enough blood, which may lead to shock.
Some concerning signs accompanying very low blood pressure to look out for include:
- rapid, shallow breathing
- very weak but rapid pulse
- cold, clammy skin
- blue hue to the skin
Anyone experiencing these symptoms should seek emergency medical attention.