Systolic vs Diastolic: Different Heart Risks for Different Readings

Cardiovascular disease risk varied depending on systolic and diastolic blood pressure readings

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) High blood pressure increases the risk of stroke, heart attack and other health problems. A closer look at blood pressure readings may foretell the specific type of health troubles that lie ahead.

Systolic pressure (the top number) is the measurement of maximum force of the blood in the arteries, while diastolic (the lower number) is the pressure measurement when the heart is relaxed. If either number is high, it can signal a health problem.

A new study has discovered that specific health risks may be identified according to which number is elevated.

"Have your blood pressure checked at least once a year."

Eleni Rapsomaniki, PhD, a medical statistician with The Farr Institute for Health Informatics Research in London, and colleagues reviewed electronic health records of 1.25 million patients, aged 30 years and older, who had no cardiovascular disease at the start of this investigation.

Dr. Rapsomaniki and team followed these patients for an average of about five years and recorded 83,098 first presentations of cardiovascular disease.

All of the patients had blood pressure readings taken. High blood pressure, or hypertension, is often called a “silent killer” because it can damage the heart, kidney and brain, yet have no symptoms. It takes a blood pressure reading to find out if pressure in the arteries is beyond the normal range.

For every age group, the lowest risk for heart disease was for those individuals who had a systolic pressure of 90 to 114 mm Hg (millimeters of mercury) and a diastolic blood pressure of 60 to 74 mm Hg.

Traditionally, the American Heart Association has defined normal blood pressure as less than 120 for systolic and less than 80 for diastolic.

Dr. Rapsomaniki and team observed that those with high systolic pressure were more likely to have intracerebral hemorrhage (stroke caused by bleeding within the brain rather than a clot), subarachnoid hemorrhage (an often deadly bleeding in the area between the brain and the thin tissues that cover the brain) and stable angina (chest pain or discomfort due to coronary heart disease).

Compared to diastolic blood pressure, elevated systolic pressure also had a greater influence on the risk of heart attack and peripheral arterial disease.

High systolic readings, however, had a weak association with abdominal aortic aneurysm (a ballooning of the major blood vessel that supplies blood to the body), while high diastolic measures signaled a greater risk for this condition.

"Our findings do not support the widely held assumptions that systolic and diastolic pressure have similar strong associations with the occurrence of all cardiovascular diseases across a wide age range,” said Dr. Rapsomaniki in a press release.

To illustrate the harmful effects of high blood pressure, the researchers spotlighted a heart disease risk for a 30-year-old. According to their calculations, a person this age with high blood pressure (greater than 140/90 mm Hg) had a lifetime risk of developing cardiovascular disease of 63 percent, while that risk was 20 percent lower for those with healthy blood pressure.

In a related editorial comment, Thomas Kahan, MD, from the Karolinska Institutet in Stockholm, Sweden, said that more measures are needed to improve antihypertensive treatment and control, including better medication compliance and treatment and expanding the use of home blood pressure monitoring.

This study was published at the end of May in a special themed issue of The Lancet, and results will be presented at Hypertension 2014, the Joint Meeting of the European Society of Hypertension (ESH) and International Society of Hypertension (ISH) in Athens, Greece, June 13-16, 2014. The research was support by funding from Medical Research Council, National Institute for Health Research and Wellcome Trust.

Review Date: 
May 29, 2014
Last Updated:
May 31, 2014