Can having low blood pressure make you tired

• While having high blood pressure isn't good, low blood pressure isn't necessarily dangerous.
• However, symptoms like nausea and blurred vision alongside low blood pressure are red flags.
• Low blood pressure can be caused by dehydration, pregnancy, diabetes, and certain medications.

Fatigue, blurred vision, and lightheadedness are just some of the common symptoms of low blood pressure, aka hypotension. It usually occurs when your blood pressure reading is lower than the healthy range of 90/60 to 120/80 mm Hg. However, what's considered low for one person might be normal for another. 

"Low blood pressure is really relative to what a person's blood pressure normally is. There are some patients whose blood pressure is normally 90/60, and they do not have any symptoms, so this would not be deemed low blood pressure for them," says Joyce Oen-Hsiao, MD, director of clinical cardiology at Yale Medicine and assistant professor of clinical medicine at Yale School of Medicine.

Blood pressure normally fluctuates throughout the day depending on stress levels and dietary choices, but conditions like pregnancy, dehydration, and blood loss can cause blood pressure to become lower than usual.

Learn about the symptoms and causes of low blood pressure, and know when you should seek medical attention.

Severe hypotension, or having dangerously low blood pressure levels, can cause the body to go into shock where the brain and organs can't function properly. It can manifest additional symptoms, such as:

Symptoms of severe low blood pressure (hypotension): 

• Shallow breathing
• Weak and rapid pulse
• Cold, clammy skin
• Confusion
• Pale/whitish  skin tone

What causes low blood pressure? 

Symptoms of low blood pressure are driven by poor blood flow, says Clyde W. Yancy, MD, MSc, chief of cardiology at Northwestern University Feinberg School of Medicine and associate director of the Bluhm Cardiovascular Institute of Northwestern Memorial Hospital.

"Patients generally don't feel well when their pressure is low, and usually need to sit or lay down in order to feel better," says Oen-Hsiao.

According to Oen-Hsiao, your blood pressure may drop if you haven't eaten or are dehydrated, or you accidentally took your medication twice. Low blood pressure may also be a symptom of underlying medical conditions such as anemia, so your health provider may perform blood tests to check.

In general, "patients [who are] most likely to experience low blood pressure are older patients over 65 years, patients who have nervous system issues — like diabetic peripheral neuropathy or Parkinson's — and some patients who get hemodialysis [a treatment where a machine removes waste from the blood]," says Oen-Hsiao.

What is the lowest blood pressure that is safe?

Low blood pressure on its own is not life-threatening. So, if you have a blood pressure reading that's lower than normal, but you feel alright, then you don't need to worry. 

"The lowest blood pressure that is considered 'safe' is a blood pressure where the patient doesn't have symptoms such as dizziness, light-headedness, and almost passing out," says Oen-Hsiao.

Insider's takeaway

Low blood pressure or hypotension is generally characterized by a reading below 90/60 mm Hg. You should keep track of what your normal blood pressure is so you can recognize when it dips. Blurred vision, lightheadedness, and nausea are common symptoms, but clammy skin and persistent symptoms that don't improve may warrant a trip to the emergency room.

Blood pressure normally changes throughout the day, but blood loss, dehydration, and certain health problems can result in low blood pressure. If you're having negative symptoms of low blood pressure, you can raise your blood pressure back to normal by drinking more water, increasing your sodium intake, or treating the underlying medical condition that caused low blood pressure in the first place.

"The best way to treat low blood pressure is to make sure that you sit or lay down. This helps to get as much blood up to the brain as possible," says Oen-Hsiao. "If your symptoms do not go away in an hour after resting and drinking water, call your doctor."

Carla Delgado

Freelance Reporter, Insider Reviews

Carla is a Filipino freelance health & culture journalist with bylines in Insider, Architectural Digest, Elemental, Observer, and Mental Floss. Outside of writing, she works for local theatre productions as a stage manager and assistant sound operator. Learn more about how our team of experts tests and reviews products at Insider here.

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Medically Reviewed by Melinda Ratini, DO, MS on January 14, 2021

Your doctor may say you have low blood pressure when your numbers are lower than 90 over 60. The medical term is "hypotension." But it isn't always a problem. Unlike high blood pressure, doctors usually don't use a standard set of numbers to figure out if you're ill. But if you also have symptoms like dizziness and nausea, it could be a sign that your blood pressure is too low for good health.

A cuff linked to a special device tightens around your arm to get two measurements. The top number, or "systolic," notes the pressure your blood makes against your artery walls when the heart beats. The bottom number, or "diastolic," measures the pressure between beats, while the heart is relaxing and filling with blood. You can get readings in your doctor's office or at home.

Your brain usually shows the first symptoms of hypotension. Besides dizziness and nausea, your spirits might be low, you might lack energy, and find it hard to think straight. Some people feel lightheaded enough to faint or notice cold, clammy skin, faster breathing, blurry vision, or chest pain. If your low pressure is caused by dehydration, you also might feel unusually thirsty. 

Sometimes your blood vessels widen. That means there's more space for blood to spread out, which puts less pressure on the walls of those vessels. Some drugs, especially a type called vasodilators, can cause this. So can spinal injuries that damage certain nerves, serious bacterial infections, and allergic reactions. Hormone problems like Addison's disease, which weakens the adrenal glands, can also do it.

Less blood means less pressure on your veins and arteries. An injury might cause you to bleed -- either outside your body where you can see it, or inside. It might also happen if you don't get enough to drink, your blood vessels leak fluid, or you have a blood condition called anemia. Sometimes your kidneys get rid of too much fluid because of illness or certain drugs, like diuretics.

The more blood your heart pumps per minute, the higher your blood pressure. Certain medications, along with hormone problems, heart damage, or misfiring electrical signals, can make your heart beat too slowly, which lowers that pressure. Or it could be that your heart is not as strong as it used to be because of a heart attack, heart failure, or problems with the valves, and so doesn't pump as much blood per beat.

Normally when you stand suddenly, your body sends a signal to your brain that says "Hey! We just dropped a bunch of blood down to the legs and belly, and we need to pump some more back upstairs before you get dizzy and pass out!" But sometimes, your brain doesn't get the message quickly enough and you start to feel lightheaded. You might even faint. Your doctor might call this problem "orthostatic hypotension" or "vasovagal syncope."

After you're on your feet for a while, blood can start to pool in your legs. If your brain doesn't tell your heart to pump enough to keep your blood pressure up, it might drop low enough to make you dizzy and nauseous. You might even pass out. Your doctor might call this "neurally mediated hypotension." Like a bad relationship, the problem is poor communication, in this case, between the heart and brain. 

Once your doctor knows your symptoms, blood tests can help diagnose the reason for your low blood pressure. An electrocardiogram, ultrasound, and other tests check your heart health. The Valsalva maneuver observes nerve signals that control your heart and blood vessels, and a "tilt table" test looks at how your body responds to position changes.

It depends on the cause. You may need to the treat the conditions that are giving you low blood pressure. If medication is the problem, you may need to change it or lower the dose, but always talk to your doctor first. Other drugs can help increase your blood pressure if needed, and compression socks can help push blood up from where it pools in your legs. If you don't have bothersome symptoms, you might not need treatment.

You can help lessen the symptoms of low blood pressure at home.

• Add a bit more salt back into your diet, but check with your doctor first.
• Drink more water (unless your doctor has restricted your fluid intake). It keeps your blood volume up, which raises blood pressure.
• Cut back on alcohol. It can dehydrate you and lower blood volume and blood pressure.
• Eat multiple, small meals that are low-carb, instead of three big ones, if your pressure drops after eating.

If you feel confused or notice fast, shallow breathing, a weak, rapid pulse, and cold, clammy skin, you may be in shock (extreme hypotension). Get to an emergency room right away. But lower blood pressure numbers, especially without other symptoms, aren't usually a sign of a big problem. Talk to your doctor if you start to feel dizzy or lightheaded as well. 

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