Most people know the two figures a blood pressure cuff produces, but there is a third number worth watching: pulse pressure. It offers a window into how flexible the arteries are, which is a marker of cardiovascular health.
Pulse pressure is the gap between the top (systolic) and bottom (diastolic) numbers. Systolic measures the force on the arteries when the heart contracts and pushes blood through the body, while diastolic measures the pressure when the heart rests between beats. Someone with a reading of 120/80 mm Hg has a pulse pressure of 40 mm Hg, considered normal.
Doctors usually watch for high pulse pressure, a sign of stiff blood vessels, though it has not been widely used to diagnose illness, said Dr. Charles Hong, chair of medicine at Michigan State University’s College of Human Medicine. Even so, a widened reading is an established risk factor for heart disease and stroke and may signal conditions such as atherosclerosis, the buildup of plaque in the arteries.
High pulse pressure is also tied to cognitive decline, independent of blood pressure. Research published last year in Hypertension suggested it may slow processing speed by disrupting white matter in the brain. A new study published June 3 in Neurology found a link between high pulse pressure and a greater risk of death related to dementia in some people.
Geneticist Laura Raffield of the University of North Carolina School of Medicine, who helped write the new study, said she was surprised this lesser studied measure showed such a strong connection. Her team analyzed data from the REGARDS study, focusing on roughly 9,000 adults with an average age of 64. After 14 years, more than 450 had died of a cause related to dementia. Those with a higher genetic risk score for elevated pulse pressure faced a 16 percent greater risk, while other conditions showed no statistically significant tie.
Pulse pressure tends to widen with age and rises during exercise, but a sustained level above 40 mm Hg may be harmful. The Mayo Clinic flags readings over 60 mm Hg as a heart disease risk, especially in older adults.
The encouraging news is that pulse pressure can be lowered. Treating blood pressure reduces it, said Dr. Steven Nissen of the Cleveland Clinic, who also recommends the DASH diet and regular exercise to protect long term brain and heart health.
