After standing, a fall in blood pressure

Known as orthostatic hypotension, this condition can leave people dizzy and lightheaded. For some, it may also be a harbinger of heart disease.

Have you ever felt a bit woozy just after standing up? When you transition from sitting to standing, gravity causes blood to pool in your legs. Sometimes — especially if you're dehydrated or overheated — it takes your body a moment to push blood upward, causing a brief delay in blood flow to the brain.

For most people, this phenomenon occurs just once in a while and usually isn't a serious problem. But age, some medications, and certain medical conditions can interfere with the body's normal mechanism for regulating blood pressure (see "Responding to pressure: The role of baroreceptors"). If that happens, your blood pressure may drop dramatically when you stand up. Known as orthostatic hypotension (OH), the problem affects about 5% of people younger than 50. But up to 20% of people ages 70 and older may have OH.

Several diseases, including diabetes, Parkinson's disease, and cancer, can contribute to the problem, which is also known as postural hypotension. Now, new research adds to the suspected connection between OH and cardiovascular disease.

Elevated risk to heart and head

The study, published in the May 7, 2018 Journal of the American Heart Association, tracked more than 9,100 middle-aged adults (3% of whom had OH) for more than two decades. Researchers found that people with OH had a higher risk of future heart attack, heart failure, and stroke than those without the condition. They were also more likely to have early signs of heart disease, such as plaque buildup in the carotid arteries (which supply blood to the brain) and elevated levels of blood proteins indicating heart damage.

Orthostatic hypotension could be a red flag for latent cardiovascular disease. It's important to be aware of this possible link because some of the treatments for OH could make heart disease worse.

A two-way street?

The link between the two conditions could be bidirectional. One possible explanation is that periodic bouts of insufficient blood flow to the heart and brain caused by OH may strain those organs, causing damage that accumulates over time. Alternatively, the gradual buildup of plaque or thickening of key arteries may affect the body's blood pressure regulation mechanism, triggering OH.

Not everyone who experiences dizziness has OH. And those with the condition won't necessarily experience cardiovascular problems. But diagnosing OH is important for avoiding other, more common complications such as faints and falls that result from dizzy spells.

Detecting the problem

If you experience bouts of dizziness after standing, ask your doctor to measure your blood pressure after you've been sitting quietly for five minutes and again within one and three minutes after you stand up. After you stand up, if your systolic pressure (the first number of the reading) falls more than 20 mm Hg or your diastolic pressure (the second number) drops at least 10 mm Hg, you may have OH. The prevalence is higher in older people because they're more likely to take drugs that can worsen OH, such as beta blockers (which reduce the heart rate) and alpha blockers (which can reduce blood pressure; they're used in men to treat an enlarged prostate).

Treatment advice

In addition to a getting a careful review of your medications, if you have signs of OH, doctors recommend that you drink water throughout the day, drink little or no alcohol, and stand up slowly, especially when rising from bed in the morning. Compression stockings that squeeze the legs may also help.