Blood pressure, or BP, is the force of blood against the blood vessel walls. Blood is pumped throughout the entire body by the heart.
Blood pressure is measured with two different numbers.
The first or top number is called systolic pressure. This is the pressure while the heart is beating.
The second or bottom number is called diastolic pressure. It’s the pressure while the heart rests between beats. Diastolic pressure is typically lower than systolic pressure.
Both are measured in millimeters of mercury (mm Hg).
Typical healthy blood pressure is about 120/80 mm Hg. It’s not uncommon for the numbers to fluctuate slightly throughout the day, however, regardless of your overall health.
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To help make sure every part of your body — including the brain, heart, and lungs — is getting plenty of blood and oxygen, your blood pressure naturally changes during the day.
Your body constantly adjusts and balances your blood pressure. The position of your body may impact your blood pressure. For example, if you stand up suddenly, it may drop for an instant. Your blood pressure also lowers when you’re resting or asleep.
So, low blood pressure may not be a cause for concern or come with any other worrisome symptoms.
On the other hand, some health conditions can result in low blood pressure. This can lead to too little blood and oxygen in some parts of the body. Treating the underlying condition helps to raise blood pressure.
The symptoms of low blood pressure can include:
- blurred vision
- feeling cold
- feeling thirsty
- an inability to concentrate
- rapid, shallow breathing
Low blood pressure from medications, shock, or stroke
Some medications can cause low blood pressure. These include drugs to treat high blood pressure and other conditions, such as:
- angiotensin II receptor blockers
- angiotensin-converting enzyme (ACE) inhibitors
- beta-blockers (Tenormin, Inderal, Innopran XL)
- calcium channel blockers
- diuretics or water pills (Lasix, Maxzide, Microzide)
- erectile dysfunction drugs (Revatio, Viagra, Adcirca, Cialis)
- Parkinson’s disease medications such as Mirapex and levodopa
- tricyclic antidepressants (Silenor, Tofranil)
Shock is a life threatening condition. It can happen in response to a number of emergency conditions. These include:
Shock leads to low blood pressure, but low blood pressure can also cause your body to go into shock. Treatment may involve raising blood pressure by IV fluids or blood transfusions.
Treating the cause of the shock often helps to raise blood pressure.
For example, in anaphylactic shock, an injection of epinephrine (EpiPen) helps to quickly raise blood pressure. This can be lifesaving for someone having a severe allergic reaction to peanuts, bee stings, or other allergens.
In a first aid situation, it’s important to keep the person experiencing shock warm and monitor them until medical help arrives. Call 911 or local emergency services as soon as possible.
With emergency help on the way, the next thing to do is elevate the person’s legs 6-12 feet off the ground using whatever item is available to you. Keep the person warm by covering them with a blanket or coat. Newspapers can be used in a pinch.
Stroke is a leading cause of death. It’s also a major cause of serious and long-term disability.
High blood pressure is a major cause of stroke. It’s important to control blood pressure to prevent strokes, and to keep them from happening again.
If you’re dealing with hypotension, the first step is making an appointment with your doctor. After discussing your medical history, lifestyle, and other factors, your doctor may change your medication or suggest certain lifestyle changes to get to the root of the issue.
It’s important not to stop taking any medications or change dosages without talking to a healthcare professional first. The same is true of dietary or other changes.
1. Drink plenty of water
Dehydration can sometimes lead to low blood pressure. Some people may have hypotension even with mild dehydration.
You can also get dehydrated by losing water too quickly. This can happen through vomiting, severe diarrhea, fever, strenuous exercise, and excess sweating.
Medications such as diuretics may also cause dehydration. Drink more water by using a portable water bottle. Use an alarm or timer to remind you to take a sip.
2. Eat a balanced diet
Low blood pressure and other side effects may occur if you’re not getting enough nutrients.
Low levels of vitamin B12, folic acid, and iron can cause anemia. This condition happens when your body can’t make enough blood and can cause low blood pressure.
Your doctor may recommend changes to your daily diet and taking supplements.
3. Eat smaller meals
You can get low blood pressure after eating a big meal, although this is more common in older adults. This happens because blood flows to your digestive tract after you eat. Normally, your heart rate increases to help balance blood pressure.
You can prevent low blood pressure by eating smaller meals. Also, limiting your carbs can help keep blood pressure more stable after eating. Here are more suggestions for foods you can eat and eating habits you can practice.
4. Limit or avoid alcohol
Drinking alcohol can lead to dehydration. It can also interact with medications and cause low blood pressure.
5. Eat more salt
Sodium helps to raise blood pressure. However, it can raise blood pressure too much. It can also lead to heart disease. Ask your doctor how much is right for you.
Add table salt to whole, unprocessed foods. This helps to control how much salt you’re eating. Avoid refined and processed salty foods.
6. Check your blood sugar
Diabetes and high blood sugar levels may lead to low blood pressure. Volume depletion can occur from the diuresis that follows high blood sugar levels. This is when your body tries to expel glucose via increased urination.
Consider using a home monitor to check your blood sugar levels throughout the day. See your doctor to find out the best diet, exercise, and medication plan to help balance blood sugar levels.
7. Get your thyroid checked
A simple blood test can determine whether you have hypothyroidism. You may need medication and a new nutrition plan to help boost your thyroid function.
8. Wear compression stockings
Elastic stockings or socks can help prevent blood from pooling in your legs. This helps to relieve orthostatic or postural hypotension which is low blood pressure due to standing, laying down, or sitting too much.
People who are on bed rest may need compression braces to help pump blood from the legs. Orthostatic hypotension is more common in older adults. It happens to up to 11 percent of middle-aged people and 30 percent of older adults.
9. Take medications
Your doctor may prescribe medications to help treat low blood pressure. These drugs help to treat orthostatic hypotension:
- fludrocortisone, which helps to raise blood volume
- midodrine (Orvaten), which helps to narrow blood vessels to raise blood pressure
If someone’s BP is dangerously low from sepsis, other medications may be used to raise blood pressure. These include:
- alpha-adrenoceptor agonists
- vasopressin analogs
10. Treat infections
Some serious bacterial, viral, and fungal infections can cause low blood pressure. Your doctor can find out if you have an infection with a blood test. Treatment includes IV antibiotics and antiviral drugs.
There are several causes of low blood pressure. Some are temporary and can be easily fixed. Low blood pressure may also be a sign of a health issue or emergency condition. Treatment may be necessary.
Several health conditions can cause low blood pressure. These include:
- Addison’s disease (low adrenal hormones)
- anaphylaxis (a serious allergic reaction)
- blood loss
- bradycardia (low heart rate)
- diabetes or low blood sugar
- heart attack or heart failure
- a heart valve problem
- hypothyroidism (low thyroid hormone)
- liver failure
- parathyroid disease
- septic shock (the result of a serious infection)
- orthostatic hypotension or postural low blood pressure
- trauma or head injury
Diagnosing and treating these conditions can help balance blood pressure. Your doctor may recommend simple tests such as:
- blood tests to check hormone levels, blood sugar levels, and for infections
- an electrocardiogram (ECG) or Holter monitor to check heart rhythm and function
- an echocardiogram to check your heart health
- an exercise stress test to check your heart health
- a tilt table test to check low blood pressure due to changes in body position
- the Valsalva maneuver, a breathing test to check for nervous system causes of low blood pressure
Having low blood pressure once in a while isn’t likely a cause for concern.
Tell your doctor about any related symptoms. Keep a journal of your symptoms and what you were doing when they began.
This can help your doctor diagnose the cause of your low blood pressure, especially if you’ve tried making changes to your diet and lifestyle and still aren’t seeing your BP at a healthy level.
Learn to recognize triggers and symptoms. Put your head down or lay down if you feel dizzy or lightheaded. These symptoms usually pass quickly. Children and teens who have low blood pressure due to body position typically grow out of it.
If you have orthostatic hypotension, avoid symptom triggers, such as standing too much.
To help make sure every part of your body — including the brain, heart, and lungs — is getting plenty of blood and oxygen, your blood pressure naturally changes throughout the day. It may dip if you stand up suddenly, and it typically decreases during periods of sleep or rest.
Hypotension, or low blood pressure, isn’t automatically a cause for concern. Some health conditions lead to hypotension, so it’s important to talk with your doctor about any symptoms you may be experiencing.