Blood pressure is a measure of the force of blood against a person’s arteries as the heart pumps blood through the body. High blood pressure—also called hypertension—is associated with increased risk of heart attacks, strokes and kidney disease. Treating high blood pressure either with a healthy lifestyle or with medication significantly reduces the risks of these health problems.
How many people have high blood pressure? About one-third of all people in the United States have high blood pressure. But African Americans are even more likely to experience it. Nearly two-thirds of people over age 60 have high blood pressure. New recommendations from the American Heart Association state that a healthy blood pressure is 120/80 mmHg or less. This means even more people are now considered to have high blood pressure. Elevated blood pressure is the most common problem addressed in primary care doctors’ offices.
What are the symptoms of high blood pressure? Most people with high blood pressure do not feel any effects until they experience a heart attack, stroke or kidney failure. About half of people in the United States with high blood pressure are unaware of their condition.
What causes high blood pressure? The way people eat has a dramatic influence on blood pressure. Research shows that too much sodium in the diet is associated with elevated blood pressure. The Food and Drug Administration recommends limiting sodium intake to 2.3 grams per day. Although the American Heart Association recommends even less, the average American eats much more than this. Processed foods and food from restaurants, especially fast food, are especially high in sodium.
Although many people are aware that sodium affects blood pressure, fewer realize that getting too little potassium also raises blood pressure. Potassium is found in fresh fruits and vegetables like citrus, melons, squash, tomatoes and root vegetables. Boiling food or processing food for large-scale production often removes much of the potassium. The National Academy of Medicine estimates that 98 percent of people in the United States do not get enough potassium. This finding suggests that potassium deficiency could be the most common nutritional deficiency in the United States. Researchers in the renal-electrolyte division at the University of Pittsburgh School of Medicine are currently working to better understand how potassium influences blood pressure.
Many other factors also influence blood pressure. These include:
Alcohol—Too much alcohol can also increase blood pressure. The American Heart Association recommends fewer than one drink per day for women and two drinks a day for men.
Weight—Being overweight increases blood pressure. Each year, the percentage of overweight people in the United States increases, which likely contributes to more people having high blood pressure.
Exercise—Not getting enough exercise also contributes to higher blood pressure. Exercise that is vigorous enough to cause breathlessness tends to open up blood vessels, which lowers blood pressure.
Other—Other conditions like high cholesterol and smoking cause stiffening of blood vessels and also increase blood pressure. Importantly, increased blood pressure also stiffens blood vessels, meaning that having high blood pressure makes it likely that a person’s blood pressure will go up in the future. The good news is that lowering blood pressure now reduces the risk that blood pressure will increase more.
How is high blood pressure different in African Americans? The reasons high blood pressure is more common in people with African heritage remain unclear. Blood pressure in African Americans appears to be more sensitive to sodium. This makes it even more important for African Americans to eat a healthy diet, rich in fruits and vegetables, with limited sodium.
How can high blood pressure be prevented or controlled? Healthy eating is one of the best ways to prevent or treat high blood pressure. Eating less sodium and more potassium by replacing processed foods with fresh fruits and vegetables can improve blood pressure as much as being on one blood pressure-lowering medication. One of the most effective ways to eat less sodium and more potassium is to cook at home. Restaurants often use processed ingredients that have removed potassium and replaced it with sodium. Losing weight also lowers blood pressure. Research has shown that for every 20 pounds lost, blood pressure decreases by 10 mmHg—similar to the decrease with some blood pressure medications. Finally, an active lifestyle with regular exercise can reduce blood pressure. When these measures fail to lower blood pressure enough, medication may be necessary.
Elevated blood pressure affects most people in the United States as they age. Preventing or treating high blood pressure reduces the risk of heart attacks, strokes and kidney disease, making it important to see a doctor regularly to make sure blood pressure levels stay in the healthy range.
What studies are ongoing? The RESET-BP study at the University of Pittsburgh is examining whether increased activity at work, through the use of a standing desk, can improve blood pressures. Researchers are looking for adults who work at a desk and have elevated blood pressure but who are not currently on blood pressure medication.
Evan C. Ray, MD, PhD, FASN, is Assistant Professor of Medicine, Renal-Electrolyte Division, UPMC
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