Feeling Dizziness When Standing Up? Here’s What’s Causing It

Lightheadedness when standing up is common

Have you stood up too quickly and suddenly felt dizzy? Depending on the cause, it may not be a long-term problem. But if you feel faint or actually lose consciousness, talk to your doctor as soon as possible.

“The sensation of almost fainting is known as ‘presyncope,’” says Lia Crispell, a certified registered nurse practitioner at Geisinger. “It occurs when the brain isn't receiving enough blood, oxygen or glucose to function properly, even for a brief moment.”

Common causes of lightheadedness

Many people who have an episode of presyncope brush it off and carry on with their day. “This isn’t a good idea since some of the causes can be serious. It’s always best to get a diagnosis from a doctor,” says Ms. Crispell. Dizziness can sometimes signal an underlying medical condition.

Potential causes of presyncope include:

Orthostatic hypotension

This condition, also known as postural hypotension, causes you to feel lightheaded when standing up. It happens when blood pools in your legs and feet — especially when you sit or lie down for a while — and doesn't make it up to your brain fast enough. Anyone can have orthostatic hypotension, but it's more common if you’re on certain medications or as you age.

Heart arrhythmia

This abnormal heart rate condition is when your heart beats too quickly, too slowly or in a way that suddenly reduces blood flow to the brain. Your smartwatch may even alert you about arrhythmia. Discuss this with your doctor.

Medications

Certain medications for pain, heart conditions and high blood pressure can impact your circulatory system, potentially leading to dizziness. Feel faint frequently? Ask your doctor about adjusting your dose. You may need a different amount of medication as you age, your weight changes or the drugs you take change.

Dehydration

Not drinking enough fluids can lead to nausea, weakness, dizziness, low blood pressure and fainting. Happily, rehydrating can quickly relieve these symptoms. Drink plain water, sports drinks or oral rehydration solutions. Avoid caffeine and alcohol.

Low blood sugar

Did you skip a meal, and now feel dizzy? Your blood sugar might be low, especially if your body is under stress. Frequent dizziness or shakiness between meals might be a sign of diabetes or hypoglycemia, so visit your doctor.

Anemia or low iron

Iron deficiency could make you dizzy when standing up. If you have low iron, known as anemia, your blood lacks healthy red blood cells or hemoglobin, which carry oxygen to your organs — including your brain. The hallmark of anemia is tiredness, but it can also cause you to feel faint and dizzy.

Menstruating women — especially those with severe periods — are most likely to have low iron. It’s also more common in those who are pregnant or have chronic conditions like celiac disease. A healthcare provider can test your blood to diagnose if you’re anemic.

Autonomic neuropathy

This nerve disorder disrupts electrical signals between your brain, heart, blood vessels and sweat glands. Feelings of faintness can arise from the neuropathy’s impact on your heart rate and blood pressure.

Stress and panic attacks

Anxiety attacks may cause you to breathe rapidly and deeply, which can contribute to feelings of lightheadedness and dizziness.

What to do if you feel faint

When that lightheaded sensation hits, find a safe spot to sit or lie down, and put your head between your knees.

“The most crucial step if you feel faint is to get to a secure location,” says Ms. Crispell. “This way, if you do lose consciousness, you can avoid injury from a fall or bumping your head.”

Once the faintness passes, reach out to your healthcare provider for a follow-up. A qualified medical professional can help determine the exact cause of your presyncope.