Blood pressure is generally considered too low when it drops below 90/60 mmHg. That means a systolic reading (the top number) under 90 or a diastolic reading (the bottom number) under 60. But the real threshold depends less on a specific number and more on whether you’re experiencing symptoms. Some people walk around with naturally low blood pressure their entire lives and feel perfectly fine. It only becomes a medical concern when it causes noticeable problems or signals something else going on in your body.
What Low Blood Pressure Feels Like
The most common symptom is dizziness or lightheadedness, especially when you stand up quickly. You might also notice blurred vision, difficulty concentrating, nausea, or a general sense of fatigue that doesn’t improve with rest. In more pronounced drops, fainting can occur.
These symptoms happen because your brain and organs aren’t getting enough blood flow. Your heart pumps blood through your arteries under pressure, and when that pressure falls too low, gravity wins. Blood pools in your lower body instead of reaching your brain efficiently, which is why standing up tends to be the worst trigger.
When blood pressure drops severely, the body can go into shock. Signs include cold, clammy skin, a rapid or weak pulse, shallow breathing, and confusion. This is a medical emergency that requires immediate treatment.
Types of Low Blood Pressure
Not all low blood pressure works the same way. The type you have tells you a lot about why it’s happening and what to do about it.
Orthostatic Hypotension
This is the most common type. It happens when you stand up and your blood pressure drops suddenly. Normally, when you go from sitting or lying down to standing, roughly 500 to 1,000 mL of blood shifts from your central circulation into the veins of your legs and abdomen. Your nervous system is supposed to compensate instantly by tightening blood vessels and slightly increasing your heart rate. Orthostatic hypotension means that reflex isn’t working well enough.
Symptoms tend to be worse in the morning. Overnight, your body loses fluid through natural processes, so your blood volume is at its lowest point when you first wake up. Heat, alcohol, dehydration, prolonged bed rest, and certain medications all make it worse. Older adults are particularly susceptible because the reflexes that regulate blood pressure slow down with age.
Postprandial Hypotension
This type hits within two hours after eating a meal. Your digestive system needs extra blood flow to do its work, and in some people, blood pools in the abdomen without adequate compensation elsewhere. Large meals and meals heavy in carbohydrates are the most common triggers. Alcohol with food makes it worse.
Neurally Mediated Hypotension
Sometimes called a vasovagal response, this happens when your nervous system overreacts to a trigger like prolonged standing, emotional stress, pain, or even the sight of blood. Your heart rate and blood pressure drop simultaneously, reducing blood flow to the brain and causing fainting. This is the classic “passing out at the sight of a needle” scenario, and while frightening, it’s usually not dangerous on its own.
Common Causes
Low blood pressure can stem from a wide range of conditions. Heart problems are a major category: heart failure, heart valve disease, a very slow heart rate, and even a previous heart attack can all reduce the pressure your heart generates.
Hormonal and endocrine conditions also play a role. Addison’s disease, which affects the adrenal glands, can cause blood pressure to drop. Diabetes can contribute too, partly through its effects on blood sugar and partly through nerve damage that disrupts the body’s ability to regulate blood pressure. Low blood sugar on its own, from any cause, can lower blood pressure.
Nutritional deficiencies are an underappreciated cause. Low levels of vitamin B-12, folate, or iron can prevent your body from producing enough red blood cells, a condition called anemia. Fewer red blood cells means reduced blood volume and lower pressure.
Medications are one of the most frequent culprits, particularly blood pressure drugs, diuretics (water pills), and certain antidepressants. If your blood pressure dropped after starting or adjusting a medication, that connection is worth raising with your prescriber.
Dehydration deserves its own mention. When you lose more fluid than you take in, whether from illness, exercise, heat, or simply not drinking enough, your blood volume drops and your pressure follows. Severe infections, allergic reactions, and significant blood loss can also cause dangerous drops in blood pressure.
How It’s Diagnosed
A standard blood pressure cuff reading is the starting point, but a single reading doesn’t tell the whole story. Your doctor may check your blood pressure in multiple positions: lying down, sitting, and standing. A significant drop when you stand, typically 20 points or more in the systolic number, points toward orthostatic hypotension.
For cases that are harder to pin down, a tilt table test can help. You lie flat on a table that’s connected to monitors tracking your blood pressure and heart rate. The table then tilts you upright quickly while those readings are recorded continuously. If your blood pressure drops significantly or you develop symptoms like dizziness or fainting during the tilt, the test is considered positive. This test is particularly useful for diagnosing orthostatic hypotension, vasovagal syncope, and a related condition called POTS (postural orthostatic tachycardia syndrome), where your heart rate spikes abnormally when you stand.
Blood work may also be ordered to check for anemia, blood sugar problems, thyroid dysfunction, or other underlying conditions driving your low readings.
Low Blood Pressure During Pregnancy
It’s normal for blood pressure to dip during pregnancy, particularly in the first and second trimesters. Normal blood pressure during pregnancy is defined as 120/80 mmHg or lower. As the body’s blood volume expands and hormonal shifts cause blood vessels to relax, readings often drop below your usual baseline. Most of the time this is harmless, though it can contribute to dizziness, especially when standing up quickly. Blood pressure typically returns to pre-pregnancy levels by the third trimester.
Managing Low Blood Pressure at Home
If your low blood pressure is mild and not caused by a serious underlying condition, several straightforward strategies can help raise your numbers and reduce symptoms.
Drinking more water is the simplest intervention. Fluids increase your blood volume directly, and even mild dehydration can worsen hypotension. Alcohol works in the opposite direction. It’s dehydrating and lowers blood pressure even in moderate amounts, so cutting back can make a noticeable difference.
Adding more salt to your diet may help, which is the reverse of what most blood pressure advice tells you. Salt causes your body to retain fluid, which boosts blood volume and raises pressure. However, too much salt carries risks for heart health, especially in older adults, so this is a change worth discussing with a healthcare provider before making on your own.
Changing positions slowly is a practical habit that costs nothing. When you get out of bed in the morning, sit on the edge for 30 seconds before standing. If you’ve been sitting for a long time, rise gradually. For postprandial hypotension, eating smaller, more frequent meals with fewer carbohydrates can help prevent the post-meal blood pressure dip.
Compression stockings can also help by preventing blood from pooling in your legs. They’re especially useful for people with orthostatic hypotension who spend long periods standing. If lifestyle changes aren’t enough, medications that raise blood pressure or increase blood volume are available, though they’re typically reserved for cases where symptoms significantly affect daily life.