Low Blood Pressure 101 (Hypotension)

low blood pressure

Many of our readers might wish to lower their blood pressure by diets or exercise. However, things will develop in the opposite direction when they become extreme. As the “opposite” of high blood pressure, low blood pressure is another condition that is often neglected.

Johns Hopkins University study pointed out that people with blood pressure below normal for a long time are more prone to fatigue, drowsiness, and lack of energy.

Researchers conducted a 10-year study on 876 young men and women, including regular blood pressure measurements and questionnaires, which asked whether they usually feel tired easily?

They compared the subjects’ blood pressure records and questionnaire answers and found that women with systolic blood pressure averaging less than 100 millimeters of mercury (mmHg) were five times more likely to be tired and tired and mentally ill than those with higher values.

In addition, some studies have also pointed out that low blood pressure and “chronic fatigue syndrome” (CFS), people with this problem if standing for a long time, stay in a hot and stuffy environment, or exercise more intense, blood pressure will often suddenly fall. Researchers have also found that if these people’s blood pressure is kept normal, their symptoms of “chronic fatigue” will be released or even disappear.

What is low blood pressure?

There is no standard value for hypotension set by the World Health Organization. Generally speaking, normal systolic blood pressure should be between 90 and 140 millimeters of mercury (mm/Hg) and diastolic blood pressure between 60 and 90 mm/Hg. However, clinical medicine considers that adults with systolic blood pressure below 90 mmHg or diastolic blood pressure below 60 mmHg may have hypotension.

Types of Low Blood Pressure

Low blood pressure can be caused by various conditions and it is almost impossible to list all of them exhaustively here. Below are some common types of low blood pressure:

  1. 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 the legs when standing. Ordinarily, the body compensates by increasing the 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.

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.

2. Low blood pressure after eating (postprandial hypotension). This kind of low blood pressure occurs one to two hours after eating and affects mostly older adults.

Blood flows to the stomach after eating. Ordinarily, the body increases the heart rate and constricts certain blood vessels to help maintain normal blood pressure. But in some people, these mechanisms fail, causing 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.

Eating small, low-carbohydrate meals; drinking more water, and avoiding alcohol might help reduce symptoms.

3. 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.

4. Low blood pressure due to nervous system damage (multiple system atrophy with orthostatic hypotension). Shy-Drager syndrome, the rare disorder has many Parkinson’s disease-like symptoms, which 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.

What are the Symptoms of Low Blood Pressure?

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
  • Blurred or fading vision
  • Nausea
  • Fatigue
  • Lack of concentration
low blood pressure dizzy

When to Visit a Doctor?

For some skinny women, their blood pressure might be a little bit lower than the standard level. It is OK if you don’t feel any discomfort.

However, when blood pressure is lower than the usual measurement of 30 mmHg, it is important to pay attention to the symptoms, which may include dizziness, blurred vision, weakness, fatigue, chest tightness, and cold hands and feet. Acute hypotension refers to a sudden drop in blood pressure, which is usually caused by ischemia of vital organs, and in more serious cases, fainting and shock may occur.

Acute hypotensive conditions are usually more urgent. If someone around you suddenly faints, shock or lost a lot of blood, take them to the emergency room as soon as possible and ask the doctor to help treat them as soon as possible.

low blood pressure visit doctor

What to Do and Eat for Improving Low Blood Pressure?

Eat More

Weight and blood pressure are closely related, usually when weight increases, blood pressure also increases, so people who are overweight are prone to hypertension. On the contrary, people with low blood pressure and too thin (such as BMI less than 18.5) can eat fatter to achieve the ideal weight to raise blood pressure.

Eat More salt

Not everyone needs to limit salt, people with low blood pressure can eat a little salty. In addition, people with low blood pressure can drink sports drinks to replenish the sodium loss after exercising or sweating a lot.

Avoid Low Sodium Salt

The commercially promoted “low sodium salt” and “healthy and tasty salt” replace part of the sodium with potassium, which has a slight blood pressure-lowering effect.

As for people with normal blood pressure or high blood pressure, doctors also do not recommend using “low sodium salt”, especially for kidney patients and people with urinary dysfunction, because it is not easy to excrete potassium from the body and it will accumulate in the body and cause high potassium, which may lead to the irregular heart beat and heart failure.

Drink Plenty of Water

Especially in summer, sweating is easy to lose water, plus the hot weather, blood vessels dilate, blood pressure will be lower, if the body is not enough water, blood pressure will drop even lower, so usually take enough water to avoid dehydration.

Take Moderate Caffeine

Caffeine can make blood pressure rise suddenly, so doctors will remind patients with high blood pressure must limit the amount of caffeine intake. On the contrary, people with low blood pressure can pull their blood pressure up a bit by drinking tea and coffee.

Do More Lower Limb Exercises

When moving the lower extremities, muscle contraction can help blood return to the veins and increase the amount of blood output from the heart, causing blood pressure to rise, so people with low blood pressure should exercise regularly, especially to move the lower extremities, such as walking, lifting the legs while sitting or standing, to promote blood circulation, rather than standing still for a long time.

Pay Attention to the Dosage of Blood Pressure Medication and Measure Blood Pressure Regularly.

Patients with hypertension should take their medication according to the dosage prescribed by their doctor and should not adjust the dosage arbitrarily. If there is any discomfort after taking the medication, or if you find that your blood pressure varies greatly when measuring your blood pressure (e.g., it drops very low), you should tell your doctor immediately to see if you need to adjust the dosage or switch to another medication.


Low blood pressure is a chronic condition that are easily neglected. If you suffer from dizziness or chronic fatigue syndrome for unknown reasons, you might want to take a closer look at your blood pressure and see if there’s any possibility of having low blood pressure.