Controlling Your Blood Pressure Archive

Sweet drinks go down easy, but they may be hard on your heart. Aside from plain water, the healthiest choices are unsweetened tea, coffee, and flavored waters.

When you want to quench your thirst with something a little more exciting than plain old water, there are a dizzying array of choices these days. However, many of the beverages in supermarkets and convenience store aisles are loaded with added sugar. Even many of those that sound healthy (such as 100% fruit juice and vitamin-enhanced water) contain as much sugar as regular sodas.

Yes, the sugar in fruit juice is naturally occurring, as opposed to the processed sugar (usually high-fructose corn syrup) found in many carbonated and noncarbonated drinks such as sodas, vitamin water, and the like. But people should still be mindful about consuming too much fruit juice, says Vasanti Malik, a nutrition researcher at the Harvard T.H. Chan School of Public Health.

News briefs

Vitamins and supplements won't help stave off dementia, but a healthy lifestyle might, suggest new guidelines released May 19, 2019, by the World Health Organization (WHO). The WHO warns that the number of new dementia cases around the world — currently 10 million per year — is set to triple by 2050. While there's no cure for any kind of dementia (such as Alzheimer's disease and vascular dementia), the WHO says it may be possible to delay the onset of the disease or slow its progression. The key: managing modifiable risks, such as chronic disease and unhealthy habits. The guidelines recommend that you keep your weight, cholesterol, blood pressure, and blood sugar under control; get lots of exercise; and eat a Mediterranean-style diet (which emphasizes olive oil, fruits, vegetables, nuts, and fish; minimizes red meats and processed meats; and includes a moderate amount of cheese and wine). The WHO also advises that you don't smoke and you avoid harmful use of alcohol (no more than one drink per day for women, no more than two drinks for men). But don't count on supplements to help you stave off dementia. The WHO says there's no evidence that vitamin B, vitamin E, multivitamins, or fish oil supplements help reduce the risk for dementia. The agency recommends against using supplements as a means to ward off cognitive decline.

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Eating too much salt usually boosts blood pressure, but not in everyone. Understanding the genetic basis of these differences may improve treatment of high blood pressure.

Do you know someone who eats lots of salty food — pizza, pickles, pretzels, and the like — but has naturally low blood pressure? That person may be salt-resistant, which means his or her blood pressure doesn't rise very much in response to a diet high in salt (sodium chloride). In contrast, other people are salt-sensitive, which means their blood pressure rises by 5 points or more if they switch from a low-sodium to a high-sodium diet.

Unfortunately, there isn't an easy test to determine who is salt-sensitive, says endocrinologist Dr. Gordon Williams, professor of medicine at Harvard Medical School. "Still, we know that Americans eat far more salt than they actually need, so it makes sense to advise everyone cut back on salt," he says.

Ask the doctor

Q. What causes high blood pressure?

A. My answer is going to start in your back yard; stay with me. You're holding a hose, you turn on the water, and it shoots through the hose and out the nozzle. The water is moving because it's under pressure. Similarly, when your heart beats it creates pressure that enables your blood to "water" your body with the nutrients that are in your blood.

Three things affect the amount of pressure that pushes blood through your body: how forcefully the heart pumps, how much blood there is, and how narrow the smallest blood vessels are. That last one may need some explanation. When you're watering plants, and you want the stream of water to go farther, what do you do? You make the nozzle smaller. Narrowing the opening through which the water flows increases the pressure, and the water then is able to reach the distant flowerbed.

In the journals

Eating a cup of blueberries every day may help your blood pressure, suggests a new study. The results, published online Feb. 16, 2019, by The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, found that consuming 200 grams of blueberries (about one cup) daily can improve blood vessel function and decrease systolic blood pressure (the top number in a blood pressure reading).

Researchers recruited 40 healthy men and randomly gave them either a drink containing 200 grams of whole wild blueberries or a control drink (which looked and tasted much the same) every day for a month. The team also monitored the men's blood pressure as well as the flow-mediated dilation of the brachial artery in their upper arms. This measures how the artery widens when blood flow increases and is a marker of reduced cardiovascular disease risk.

Ask the doctor

Q. Why are the blood pressure readings in my right and left arm different even when they're taken within a minute or two of each other?

A. The answer depends on how big of a difference you're talking about. A difference of just a few points (that is, a few millimeters of mercury, or mm Hg) is nothing to worry about. It's actually quite normal, even when both arms are checked almost simultaneously.

Here's what you need to know about the discovery of contaminants in a popular class of heart medications.

Last summer, a number of prescription medications containing the generic drug valsartan were recalled by manufacturers after investigators found trace amounts of possible cancer-causing impurities in some of the products. Over the following months, additional lots of valsartan, as well as batches of two similar drugs, losartan and irbesartan, were also pulled from pharmacy shelves.

All three of these drugs belong to a class of medications known as angiotensin-receptor blockers, or ARBs. These drugs block the effects of a hormone that narrows blood vessels and are used to treat high blood pressure and heart failure. The recalled products also include combination drugs that contain one of those three ARBs. (See "Medication recall information" for accessing the list of affected products.)

On call

Q. I know that erectile dysfunction can be a common side effect of blood pressure medications, but can they also lower my sex drive?

A. Sexual issues are a side effect of many medications, including ones prescribed to lower blood pressure. You're correct that erectile dysfunction (ED) is mentioned most frequently. But blood pressure medicines also can decrease sexual drive or make it more difficult to reach orgasm.

On call

Q. After I have a bowel movement I sometimes get quite weak and have to lie down until the feeling passes. Why does this happen and is it cause for concern?

A. The sensation you are describing is most likely due to a reflex called a "vasovagal reaction." Here's what I mean.

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.