Estrogen seems to work by reducing the levels of LDL, low-density lipoproteins, or bad cholesterol, and triglycerides in the blood. These two substances tend to collect on arterial walls, gradually narrowing passages and making the heart work harder to move blood through the body. The good cholesterol, HDL, or high-density lipoprotiens, does not stick to vessel walls and actually seems to carry away the bad cholesterol. Certain lifestyle choices compound the problem of high blood pressure. According tot he American Heart Association the single biggest controllable risk factor linked to high blood pressure and heart disease is smoking.
Smoking constricts the blood vessels, making the heart work harder and raising blood pressure.
Smoking also raises carbon monoxide levels in the blood, depriving the heart of oxygen. Birth control pills and being overweight are also a risk factors. These risk factors are greatly compounded when combined and as a woman approaches menopause. High blood pressure is known as the silent killer because it has little or no symptoms. According to the American Heart Association, one in four Americans have the disease and one-third of them don't even know it.