Nearly half of U.S. adults have systemic hypertension. Gender (more men than women), age, and chronic conditions like kidney disease and diabetes can raise your risk. So can lifestyle choices, like smoking, lack of physical activity, and eating a high-salt diet. "Genetics have a lot to do with it, too. A young person can have hypertension with no hardening of the arteries," says Tae Yang, M.D., an interventional cardiologist at Orange Coast Medical Center in Fountain Valley, CA. If left untreated, high blood pressure can damage blood vessels and lead to heart attack, stroke, and left-sided heart failure.