A new study suggests that, for some people, very low diastolic blood pressure—the pressure when the heart is resting—increases the risk of heart tissue damage and heart disease. Recent clinical trials have supported using medication to lower systolic blood pressure—the pressure measured during a heartbeat—below 120 millimetres of mercury (mmHg). However, doing so also lowers diastolic blood pressure, and the potential consequences of this have not been closely examined.
A team of researchers combed through data on blood pressure, blood tests for heart damage, and health history from over 11,000 people participating in the Atherosclerosis Risk in Communities study.
The researchers found that people with diastolic blood pressure below 60 mmHg were twice as likely to have high blood levels of a protein that indicates heart damage as people who had diastolic blood pressures in the range of 80 to 89 mmHg. People with diastolic blood pressure in the range of 60 to 69 mmHg were over 50% more likely to have indication of heart damage. Additionally, people with diastolic blood pressure below 60 mmHg were 49% more likely to have heart disease.
In an accompanying press release, study authors stress that more research is needed but that the results suggest “for some patients, there should perhaps be modification of intensive anti-hypertensive treatment recommendations issued last year as a result of the SPRINT trial, and that physicians shouldn’t look at driving down the top blood pressure number (the systolic number) in isolation without considering implications of lowering the bottom number.”