Low blood pressure, called hypotension, is a reading below 90/60 mmHg. Unlike high blood pressure, which is almost always a concern, low blood pressure is only a problem when it causes symptoms or drops suddenly. Many people walk around with naturally low readings their entire lives and feel perfectly fine. The issue starts when your blood pressure dips low enough that your brain and organs aren’t getting the blood flow they need.
How Low Blood Pressure Feels
The symptoms are driven by one thing: reduced blood flow to your brain and other organs. That creates a recognizable set of warning signs:
- Dizziness or lightheadedness, especially when standing
- Fainting or nearly fainting
- Blurred or fading vision
- Nausea
- Fatigue, sluggishness, or unusual weakness
- Fast, shallow breathing
- Trouble concentrating or mental fog
- Unusual confusion or changes in behavior
If you only get dizzy once in a while after standing up too fast, that’s common and usually harmless. But if these symptoms are frequent, interfere with your daily routine, or come on suddenly, they point to something worth investigating.
What Causes It
Low blood pressure has a wide range of causes, from completely benign to serious. Understanding which category you fall into is what matters most.
Dehydration and Blood Volume
Your blood pressure depends partly on how much fluid is circulating in your blood vessels. When you’re dehydrated from illness, heat, not drinking enough water, or heavy exercise, blood volume drops and pressure follows. This is one of the most common and most fixable causes.
Nutritional Deficiencies
A shortage of vitamin B12 or folate can cause your body to produce red blood cells that are too large and don’t carry oxygen efficiently. This type of anemia reduces the oxygen delivery your tissues need, which can lower blood pressure and leave you feeling exhausted and lightheaded.
Heart and Circulatory Problems
Several heart conditions reduce the amount of blood your heart pumps with each beat. An unusually slow heart rate, problems with heart valves, and heart failure can all lead to chronically low pressure. These causes tend to produce persistent symptoms rather than occasional dizziness.
Hormonal Conditions
Your adrenal glands and thyroid play a direct role in regulating blood pressure. When the adrenal glands don’t produce enough of certain hormones (a condition called adrenal insufficiency), blood pressure can drop significantly. Thyroid disorders can have similar effects.
Medications
Low blood pressure is a well-known side effect of many common drugs. Diuretics (water pills), medications for high blood pressure, certain antidepressants, and drugs used for erectile dysfunction or Parkinson’s disease can all lower your readings. If your symptoms started or worsened after beginning a new medication, that connection is worth flagging to your provider.
Pregnancy
Blood pressure naturally drops during the first half of pregnancy as the circulatory system expands rapidly to support the growing fetus. This is a normal adaptation, and for most women, pressure returns to pre-pregnancy levels after delivery. But it can cause noticeable dizziness and fatigue in the meantime.
Types of Low Blood Pressure
Not all low blood pressure behaves the same way. The type you have determines when symptoms hit and what triggers them.
Orthostatic Hypotension
This is the most recognizable form: you stand up and immediately feel dizzy or see spots. It’s defined as a drop of more than 20 mmHg systolic or 10 mmHg diastolic within moments of standing. Normally, when you go from sitting to standing, about half a liter to a full liter of blood pools in your legs due to gravity. Your nervous system is supposed to respond instantly, tightening blood vessels and increasing heart rate to push blood back up toward your brain. When that reflex is too slow or too weak, your blood pressure falls before your body can compensate. Aging, dehydration, prolonged bed rest, and certain medications all make this reflex less reliable.
Postprandial Hypotension
Some people experience a significant blood pressure drop after eating, particularly after high-carbohydrate meals. Blood pools in the digestive tract to support digestion, and in some individuals, the body doesn’t compensate well enough to maintain normal pressure elsewhere. Alcohol makes this worse. It’s most common in older adults.
Neurally Mediated Hypotension
This type strikes after standing for long periods. A miscommunication between your heart and brain causes your heart rate and blood pressure to drop at the same time, often leading to fainting. It’s more common in younger people and children.
When Low Blood Pressure Becomes Dangerous
Extremely low blood pressure can progress to shock, which is a medical emergency. In shock, your organs aren’t receiving enough blood to function. The signs are distinct from ordinary low-pressure symptoms: cold, clammy skin that looks pale, a weak and rapid pulse, rapid shallow breathing, confusion (especially in older adults), and a drop in body temperature. Shock can result from severe blood loss, serious infection, a severe allergic reaction, or major heart problems. It requires immediate emergency care.
A single fainting episode in an otherwise healthy person is usually not dangerous, though it can cause injury from a fall. Repeated fainting, fainting during exercise, or fainting accompanied by chest pain or shortness of breath warrants prompt evaluation.
Lifestyle Changes That Raise Blood Pressure
For mild to moderate low blood pressure, lifestyle adjustments are the first line of defense and often the only treatment needed.
Increase salt and fluids. Salt helps your body retain water, which increases blood volume. The general recommendation for people with symptomatic low blood pressure is 3 to 5 grams of salt daily, paired with at least 60 to 100 ounces of fluid per day. If you’re adding salt through supplements, start with a small amount and increase gradually, always making sure your fluid intake keeps pace. This approach won’t work for everyone, particularly people with heart or kidney conditions, so it’s worth discussing first.
Stand up slowly. If orthostatic hypotension is your main issue, take your time transitioning from lying down to sitting, and from sitting to standing. Flex your calves a few times before you get up. This gives your circulatory system a few extra seconds to adjust.
Eat smaller, lower-carb meals. Large, carbohydrate-heavy meals pull more blood to your gut. Eating smaller portions more frequently can prevent postprandial drops.
Wear compression stockings. These apply gentle pressure to your legs, reducing the amount of blood that pools there when you stand. They’re particularly useful for orthostatic hypotension.
Limit alcohol. Alcohol dilates blood vessels and promotes dehydration, both of which lower blood pressure. Even moderate amounts can be enough to trigger symptoms in someone already prone to low readings.
Medical Treatment for Chronic Cases
When lifestyle changes aren’t enough, medications can help. The most commonly prescribed drug for chronic low blood pressure works by tightening blood vessels, which increases the resistance blood encounters as it flows and raises pressure as a result. It’s typically taken two to three times a day because its effects wear off within a few hours. Another option works by helping your body retain salt and water, increasing blood volume over time.
Treatment also depends heavily on the underlying cause. If a medication is responsible, adjusting the dose or switching drugs may resolve the problem entirely. If anemia is driving the low pressure, correcting the vitamin deficiency treats both conditions at once. The goal is rarely to hit a specific blood pressure number. Instead, it’s to eliminate symptoms and prevent falls or fainting episodes that could lead to injury.