Feeling woozy when you stand?

It might be orthostatic hypotension, a condition that can be challenging to catch and treat.

You stand up and suddenly feel unsteady on your feet. It's easy to brush off this experience as a fluke or a bug, but don't. You may have a condition called orthostatic hypotension, a temporary drop in blood pressure when you stand. It's tricky to catch.

"Blood pressure is highly variable, and depends on position, timing, the method of measurement, and circumstances associated with its measurement," says Dr. Lewis Lipsitz, chief of gerontology at Harvard-affiliated Beth Israel Deaconess Medical Center and director of the Marcus Institute for Aging Research at Hebrew SeniorLife. "It may take multiple blood pressure measurements at different times of day, lying and standing, in order to detect orthostatic hypotension," Dr. Lipsitz says.

Why it happens

When you stand, blood rushes to your abdomen and legs, and away from your head and brain, simply because of gravity. Your body's autonomic nervous system senses this and alerts the brain to make the heart beat faster and narrow your blood vessels. That restores normal blood flow to your brain and elsewhere.

But over time, the system can weaken. Heart rate may not increase and blood vessels become stiffer and less able to adapt. Blood pressure may also fall if you're dehydrated or taking medications that affect heart rate or blood vessel function. Some diseases (such as Parkinson's disease and diabetes) can also contribute to the problem.

The result is that standing up reduces blood flow to the brain, causing lightheadedness, blurred vision, or fainting. Fortunately, the condition is mild in most people: you just need to be careful when sitting up or standing up, ready to sit back down if you feel you might faint. Some people don't have any lightheadedness, but fall anyway.

What's the fix?

When orthostatic hypotension is more severe, treatment can be challenging. "Standing blood pressure may be very low, while lying blood pressure may be very high," Dr. Lipsitz explains.

He recommends treatments ranging from wearing compression stockings and elevating the head of the bed to reduce overnight blood pressure, to medications such as midodrine (Orvaten, ProAmatine) and fludro-cortisone (Florinef).

What else helps for this low blood pressure condition? "I start with a high-salt diet, then add fludrocortisone, then add nonsteroidal anti-inflammatory medications such as ibuprofen [Motrin, Advil] to force fluid and salt retention," says Dr. Randall Zusman, a cardiologist with Harvard-affiliated Massachusetts General Hospital.

A few final tips: "Drink at least one or two quarts of fluid daily to prevent dehydration, keep moving your legs when you're upright, and maintain good muscle strength in your legs," Dr. Lipsitz suggests.

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