While having blood pressure in the lower range is generally desirable, when BP is too low it may cause symptoms in which case it is known as hypotension. Low blood pressure may also cause concern because the perfusion of all tissues and organs depends on it, meaning that if it is too low our body tissues may not get enough oxygen and nutrients.
What is arterial blood pressure?
Blood pressure is defined as the pressure of the blood against the walls of blood vessels; in the case of arterial blood pressure, it is the pressure against the wall of arteries. When checking your bp, doctors will tell you two numbers, such as 120 over 80:
- the first and higher number is the maximum pressure resulting from the contraction of the heart and it’s called the systolic pressure.
- the second and lower number is the minimum pressure in the arteries when the heart is resting in between two heart beats, and it’s called diastolic pressure.
Blood pressure is regulated by the organism through several mechanisms involving the cardiovascular system, the nervous system and the endocrine system; it is also influenced by many different factors such as the emotional state, stress, exercise, aging, eating, sitting or standing, weather conditions and more.
Low bp reading range
The standard reading below which blood pressure is considered low is 90/60 mm Hg (90 over 60); as long as there are no symptoms or concerns due to the medical history, usually doctors just keep monitoring it over time without prescribing tests or treatments.
We are all different, so while some people may have their usual BP in the 90/60 range and feel good, others may experience symptoms when their systolic blood pressure is below 110.
Low BP is also more common in certain situations, like after eating or when standing up after resting, or in certain groups of people, such as the elderlies and pregnant women.
Signs and Symptoms of Low blood pressure
When blood pressure is too low or drops too suddenly you may experience the following symptoms:
- Blurred, fading, narrow vision or complete loss of vision
- Weakness and fatigue
- Cold, pale skin
- Profuse sweating
- Fast heartbeat
- Syncope (fainting)
If you experienced a syncope, you should see your doctor for a complete evaluation even if you feel better afterwards. When symptoms are severe, you should call 911 or your local medical emergency number.
Low blood pressure and high pulse
In most cases, faster heartbeat is the physiological response to a sudden decrease in blood pressure. To compensate the drop in BP, the autonomic nervous system narrows the blood vessels while the heart starts beating faster. These changes happen continuously during the day, especially when we stand up after seating or when we sit after lying down for a while. We are not usually aware of such changes because normally they are slight and happen very quickly so we don’t even experience the drop in BP, but under certain circumstances or due to certain conditions we may become aware of them.
Causes of low blood pressure
There are many possible causes for low blood pressure. They include and are not limited to:
- Prescription medication, such as those for heart conditions, for high BP, diuretics (“water pills”), for depression and other psychiatric conditions, some pain medications, or those for erectile dysfunction (Viagra, Cialis, Levitra).
- Intense exercise.
- Prolonged bed rest.
- Environmental conditions, such as high humidity and heat.
- Blood loss, including blood donations.
- Nutritional deficiencies.
- Alcohol or some recreational drugs such as weed.
- Some emotions and stress.
- Heart disease
- Endocrinological conditions
- Allergic reactions
Orthostatic hypotension is low blood pressure when assuming a standing position. This often happens in the elderlies and is dangerous as it may cause falls and syncope with possible head trauma. Orthostatic hypotension usually lasts just a few seconds up to a few minutes
Low blood pressure after eating a meal is called postprandial hypotension. After eating, the blood flows to the stomach and intestine to aid digestion. When this is not compensated by other mechanisms, such as an increase in heart rate and constriction of blood vessels, we may suffer from hypotension.
Those affected by postprandial hypotension should eat lighter meals, avoid drinking wine or other alcoholic beverages during meals and may be advised to change the timing of some medications.
Diagnosing low blood pressure
When low BP causes symptoms, you should see your doctor. He will collect your family history, medical history, ask about events or factors that may have caused the hypotension, medications you may have took and symptoms you experienced. Your doctor may take your BP in different situations like while in supine position and when standing, or after a brief physical effort. He may prescribe some tests and exams to further investigate the issue such as:
- A complete blood count (CBC)
- Serum electrolytes levels
- Hormone levels
- Electrocardiogram (ECG)
- Doppler Ultrasound
Serious conditions causing hypotension
While hypotension may be something not to worry about in many cases such as when you eat too much or you stand up too quickly after resting for a while, low blood pressure may also be the sign or symptom of other serious conditions. For this reason, it is always important to let a healthcare professional evaluate you and not perform a self-diagnosis.
When blood pressure drops too much, it causes what is known as shock, a life-threatening condition. Symptoms of shock include altered mental status, weak and rapid pulse, fast breathing, cold and pale skin, profuse sweating; when caused by anaphylaxis there may be rashes or swelling, when caused by a hemorrhage there may be visible external bleeding or there may be internal bleeding, when caused by sepsis there may be fever.
Among the many possible causes of shock there are anaphylaxis, heart failure and heart attacks, infections resulting in sepsis, brain or spinal cord damage, and severe bleeding.
Home Remedies for low bp
In case of sudden and acute low blood pressure,the first thing to do is lying down and raising the feet above heart level by placing them on a close-by elevated surface or placing 2 pillows under the ankles. If symptoms are very mild, sitting down may be enough.
Those who chronically suffer from low blood pressure should follow some simple rules:
- When getting up from bed in the morning you should sit first, wait a few moments and then slowly stand to allow more time to the organism to compensate for the drop in BP.
- When exercising drink plenty of water and don’t exert yourself too much, or rest as soon as you start feeling the first symptoms.
- During hot and humid days keep well hydrated, seek shade, take a cool shower or bath, stay indoor with the aircon, avoid exercising and eat lighter than usual.
- Take your time. Don’t rush your daily tasks, walk slowly, rest when needed.
Diet to raise low blood pressure
- Increase salt. If your diet is very low in salt not because of medical recommendations such as in kidney disease or heart disease but because of personal choice, you may consider increasing your sodium intake. It remains extremely important to keep the intake below the maximum recommended daily limit, which is 2.3 grams of sodium or about 5 grams of salt, in order to not increase the risk of cardiovascular disease.
- Avoid alcohol. Alcohol is a vasodilator and as such may cause low BP.
- Drink plenty of water. Dehydration causes lack of volume in the blood vessels. You should drink at least 2 liters of water every day, but the intake should be even higher in hot weather or if you exercise.
- Have lighter meals. The digestive system requires increased blood flow to digest food and absorb nutrients.
- Carbohydrates. Simple carbs digest very quickly, causing a greater decrease in blood pressure when compared to other food. Diminish the amount of carbohydrates in each meal or switch to whole grains to decrease their effect on BP.
- Coffee or tea. Both tea and coffee contain caffeine, which can increase the heart rate and the BP. If you drink it regularly, you may build a tolerance to the substance and the effects may become milder over time.
- Licorice. Licorice root and candies or tea made with licorice contain glycyrrhizin, a compound capable of increasing blood pressure. It is important to no consume excessive amounts of licorice as it may cause serious side effects such as decreased serum levels of potassium and abnormal heart rhythm.
- Anemia. If anemia is the cause of your low blood pressure, increase your intake of folates, vitamin B12 and iron through your diet. Eggs, red meat, liver, broccoli, spinach, asparagus are some of the foods that may help you boost the intake of those nutrients.
Supplements to raise low blood pressure
If you suffer from anemia you could discuss with your doctor about taking iron, vitamin B12 and folic acid supplements to raise your BP.
Arnica, bitter orange, ephedra, ginseng, guarana, licorice and St. John’s wort supplements may also increase your blood pressure. Since supplements, like medications, have side effects and may interact with other drugs it is always best to consult your GP before taking any.
Medicine for low bp
In some cases, your doctor may prescribe medications to prevent you from experiencing low blood pressure and the related symptoms. Depending on the cause of BP, you may be prescribed:
- Fludrocortisone (Florinef, Astonin).
- Midodrine (Gutron, ProAmatine, Orvaten)
In other cases, you BP may be too low because of medication for hypertension. In that case, they may change medicines or reduce the dose of the original one.
Compression stockings may also be advised to help raise your blood pressure.
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