Lower Blood Pressure Not Always Better For Preventing Cardiovascular Disease

A blood pressure monitorWhile it is well known that high blood pressure increases the risk of cardiovascular events such as heart attacks and strokes, scientific evidence also suggests that excessively low blood pressure can be almost as harmful as high blood pressure.

A new study, presented at the American Society of Hypertension meeting in San Francisco this month, looked at how the risk of suffering a stroke or heart attack varied with blood pressure in a group of 10,001 coronary heart disease patients.

The researchers found that those with a systolic blood pressure below 110 mmHg were 3.1 times more likely to suffer a stroke or heart attack compared to those with a blood pressure of between 130 and 140 mmHg. Those with a diastolic blood pressure below 60 mmHg were 3.3 times more likely to suffer a heart attack or stroke compared to those with a diastolic blood pressure between 70 and 80 mmHg.

The blood pressure associated with the lowest overall risk of coronary heart disease was calculated to be 140.6/79.8 mmHg, significantly higher than the 120/80 mmHg level recommended by the American Heart Association.

The researchers noted that the findings did not necessarily mean that low blood pressure causes cardiovascular disease. It is possible that low blood pressure is caused by some other factor that is in turn responsible for increased cardiovascular disease risk. Congestive heart failure for example can lead to low blood pressure due to the inability of the heart to pump sufficient blood around the body.

The research backs up the findings of similar studies that have found an increased risk of cardiovascular events in patients with pre-existing cardiovascular disease who have low blood pressure. On the other hand, healthy individuals with low blood pressure who are free from cardiovascular disease do not appear to be at an increased risk of heart disease and stroke.