6 Causes of High Blood Pressure

Medically Reviewed

One in three adult Americans has hypertension, yet more than one in five do not know they have it. Lifestyle factors account for 90 to 95 percent of cases of hypertension, or blood pressure readings that are 140/90 mm Hg or higher. High blood pressure affects approximately 67 million Americans and is a major risk factor for strokes, heart attacks, and kidney failure. In fact, more than two-thirds of individuals who have a first heart attack and three-quarters of those who have a first stroke have hypertension.

The following factors can raise blood pressure and account for most cases of essential hypertension.

1. A high-sodium (high-salt) diet

Everyone needs a tiny amount of salt to survive, but most people’s salt consumption greatly exceeds their needs. The terms “salt” and “sodium” are often used interchangeably because 90 percent of the sodium we consume is in the form of salt (which is 40 percent sodium and 60 percent chloride). Diets high in salt can raise blood pressure in at least two ways. First, sodium can cause the body to retain water, increasing the volume of blood in the arteries. Second, sodium causes small arteries to constrict, which produces greater resistance to blood flow.

2. A low-potassium diet

Potassium is a mineral like sodium; however, too little potassium (rather than too much) in your diet can increase blood pressure. Potassium also blunts the effects of dietary sodium on blood pressure. Fruits, vegetables, dairy products, and beans are rich in potassium.

3. Other dietary factors

Diets low in fruits, vegetables, and dairy products and high in saturated fat and cholesterol tend to raise blood pressure levels. In contrast, the Dietary Approaches to Stop Hypertension (DASH) diet, which emphasizes fruits, vegetables and low-fat dairy, lowers blood pressure. Vegetarian and Mediterranean-style diets also are helpful in the fight against high blood pressure.

4. Physical inactivity

If you spend more time on the couch than on your feet, you may be at risk for hypertension. A lack of exercise increases activity of the sympathetic nervous system, which can constrict blood vessels and increase blood pressure. A sedentary lifestyle also reduces the elasticity of arteries and decreases the release of hormones like nitric oxide that cause arteries to dilate. Inactivity puts you at risk for obesity.

5. Overweight and obesity

People who are overweight or obese are more likely to have hypertension than people who are normal weight. One reason is that the more weight you carry, the more blood is needed to carry oxygen and nutrients to your organs and tissues. As blood volume increases, so does pressure against artery walls, thus raising blood pressure.

6. Genetics and race

Hypertension runs in families, and genetics plays a role. In fact, researchers have identified a number of genetic variants that can increase the risk of high blood pressure. The more of these variants you have, the greater your chances of developing hypertension.

When it comes to race, blacks are at greater risk than whites for hypertension. In addition, blacks tend to develop hypertension earlier in life and to have a more severe form. Research suggests that both genes and environment are likely responsible for the higher prevalence and greater severity of hypertension in blacks.