What You Need to Know About Low Blood Pressure
The causes of low blood pressure, why it can be an issue and ways to treat it
Before any doctor's appointment, I always get a little nervous. Whether I have come in to investigate an ailment or have a yearly physical, all the bloodwork and routine tests make me anxious. The only test that never stresses me out is having my blood pressure checked.
Ever since I was a teenager, I have always had low blood pressure. Even during the late stages of my three pregnancies, when elevated blood pressure can be concerning, mine remained on the low side. I've wondered if it is an inherited trait since my dad, who is 82, also had low blood pressure most of his life.
But recently, I learned that low blood pressure, especially as you get older, isn't always good thing. Extreme heat can cause someone's blood pressure to drop suddenly, resulting in them feeling lightheaded and possibly faint. And left untreated, low blood pressure can lead to complications including acute kidney failure or an increased risk of heart attack.
Left untreated, low blood pressure can lead to complications including acute kidney failure or an increased risk of heart attack.
What is Blood Pressure?
The National Cancer Institute defines blood pressure as "the force of circulating blood on the walls of the arteries."
Although there are several types of blood pressure monitors, the one most commonly used is a cuff that is placed around the upper arm. Medical professionals regularly check blood pressure because it is a quick, non-invasive way to get a baseline reading of a patient's overall health.
A blood pressure reading has two measurements. The first number is systolic, measured when the heart beats (and blood pressure is at its highest) and the second is diastolic, measured in between beats (when blood pressure is at its lowest). Patients are told their blood pressure results as the systolic number over the diastolic number.
As outlined by the American Heart Association, there are five levels of blood pressure:
Normal (less than 120/ and less than 80);
Elevated (120-129/ and less than 80);
Types of High Blood Pressure (HBP/ hypertension):
Stage 1 (130-139/or 80-89);
Hypertension Stage 2 (140 or higher/or 90 or higher)
Hypertensive Crisis (higher than 180/and/or higher than 120), which requires immediate medical attention.
Why Low Blood Pressure Can Be An Issue
A blood pressure reading of below 90/60 is considered low. Most of the time, low blood pressure is not concerning. However, low blood pressure can lead to symptoms such as dizziness, nausea, trouble concentrating or blurred vision. People experiencing any symptoms associated with low blood pressure should consult with a medical professional.
Abnormally low blood pressure is referred to as hypotension. Jenna Liphart Rhoads, a registered nurse and CNEAdvisor at NurseTogether, explains, "Orthostatic hypotension (which occurs when you stand up from a sitting or lying down position) can cause people to become lightheaded, dizzy, or faint because blood is not being received by the brain."
In addition to orthostatic hypotension, people can also experience low blood pressure after eating a meal (known as post prandial hypotension) or after exercising or standing for a long time (neurally mediated hypotension.)
The most extreme form of hypotension is known as severe hypotension.
Liphart Rhoads explains, "With severe hypotension, one can go into 'shock' when tissues or organs do not get enough flow of blood to function properly."
Severe hypotension can be life threatening. Symptoms can include cold and clammy skin, breathing that is rapid and shallow, confusion and a weak pulse.
What Causes Hypotension?
Orthostatic hypotension is more common in people over the age of 50. Dr. Aditi Bhagat, a physician with Catholic Health says, "As you get older, the elasticity of your blood vessels decreases and blood flow to the heart and brain slows down. About nine to eighteen percent of people over fifty-five have hypotension. That number increases to twenty to thirty percent in people over seventy-five and is more frequent in hospitalized patients."
According to Bhagat, some of the reasons for a low blood pressure reading are relatively benign. "Blood pressure can be low if a person stands for long periods, overexerts themselves, drinks alcohol, or becomes dehydrated," she says.
Another common cause of low blood pressure is medication.
"Patients may go on medication because they have hypertension (high blood pressure) and the drug overcorrects, causing hypotension," says Bhagat. "Or the patient may have lowered their blood pressure through lifestyle changes, such as losing weight, and no longer requires the drug, or the dosage needs adjustment."
Medications taken for other issues (such as Parkinson's disease or depression) can also be the cause of low blood pressure.
In some cases, low blood pressure may be a more serious health issue. "Hypotension can be associated with anemia, endocrine disease, infection, or heart failure," says Liphart Rhoads. "Your heart can lose pump power due to electrical (rhythm) problems, muscle weakness, or valve dysfunction."
How to Treat Low Blood Pressure
While at-home blood pressure monitors are readily available, Bhagat cautions people about using these devices since the results can vary. "One or two low readings is not cause for alarm. A person may have just had a cup of coffee impacting the reading or need to switch positions to get an accurate read," she explains. "It is better to have a professional take the reading to avoid unnecessary worry."
Blood pressure varies among individuals and what is considered low for some patients is considered normal for others. Unless a person is experiencing symptoms, low blood pressure is not a cause for concern.
If you have low blood pressure, avoid getting up too quickly or standing for long periods and use caution when changing positions.
"The important issue is symptomatic presentation. Dizziness, fatigue, nausea or decreased mental function become triggers for immediate intervention," says Liphart Rhoads. "With mild symptoms, promptly have your doctor check orthostatic vital signs — blood pressure and pulse will be obtained in reclined, sitting and standing positions."
The doctor may also listen to a patient's heart, test for infection, check blood sugar, monitor thyroid issues and assess if any medications need to be adjusted. Patients should never attempt to change medicines without consulting their prescribing physician.
According to Bhagat, hypotension should be addressed, especially in older patients. "Dizziness and fainting caused by hypotension increase the risks of falling," she says. "We worry about patients hitting their head or breaking a hip due to undertreated hypotension."
If you have low blood pressure, avoid getting up too quickly or standing for long periods and use caution when changing positions. It's also important to engage in healthy habits, including drinking plenty of water, eating a balanced diet and limiting alcohol consumption.
Bhagat says, "Especially in the summer, it is easy to become dehydrated if you are overindulging in alcohol or spending time in the heat. I recommend patients with low blood pressure hydrate with both water and sodium and electrolyte drinks such as Gatorade."
How to Get An Accurate Blood Pressure Reading
A blood pressure reading can be influenced by many things including the way a person is sitting, if they are nervous and what they ingested within the last 30 minutes before the reading.
The CDC's website suggests the following steps to ensure an accurate reading:
- Don’t eat or drink anything 30 minutes before you take your blood pressure.
- Empty your bladder before your reading
- Sit in a comfortable chair with your back supported for at least 5 minutes before your reading.
- Put both feet flat on the ground and keep your legs uncrossed.
- Rest your arm with the cuff on a table at chest height.
- Make sure the blood pressure cuff is snug but not too tight. The cuff should be against your bare skin, not over clothing.
- Do not talk while your blood pressure is being measured.