Normally, our systolic blood pressure — the “top” number that indicates how much pressure blood exerts against artery walls when the heart beats — dips slightly when we stand. So, scientists wondered if an abnormal response — rising systolic blood pressure upon standing — might serve as an early warning sign for future cardiac events like heart attacks and strokes. Scientists were surprised to discover that even a slight uptick in blood pressure when standing up could make these events more apt to happen among young and middle-aged adults. “This finding may warrant starting blood-pressure-lowering treatment, including medicines earlier in patients with exaggerated blood pressure response to standing,” says lead study author Paolo Palatini, MD, a professor of internal medicine at the University of Padova in Italy.
Comparing Sitting Versus Standing Readings
Researchers took sitting, standing, and lying position blood pressure measurements for 1,207 young and middle-aged adults who had what’s known as stage 1 hypertension, which is defined as was defined as systolic blood pressure of 140 to 159 mmHg or diastolic blood pressure — the “bottom” number that shows how much pressure blood exerts on artery walls when the heart rests between beats — of 90 to 100 mmHg. None of the participants had ever taken blood pressure medication, and none of them had risk factors for heart attacks and strokes like type two diabetes, kidney disease, or heart disease. After an average follow-up period of 17 years, researchers identified 105 cases major cardiovascular events like heart attacks and strokes.
Significant Increase in Risk of Heart Attack or Stroke
The 10 percent of participants with the biggest spike in blood pressure upon standing were almost twice as likely to experience events like heart attacks and strokes by the end of the study, according to the study, published March 17 in Hypertension. These people had average systolic blood pressure increases of 11.4 mmHg upon standing, and all of them experienced increases greater than 6.5 mmHg. Among all the others in the study, systolic blood pressure dipped by an average of 3.8 mmHg when they stood up. Interestingly, the people with the biggest blood pressure increases upon standing had similar cardiovascular risk profiles to others in the study in many ways — they had similar activity levels, similar weight profiles, and similar family histories when it came to cardiovascular events. People with the biggest standing blood pressure spikes were, however, more likely to smoke. On the other side of the ledger, they tended to have lower total cholesterol levels as well as lower levels of “bad” LDL cholesterol. One limitation of the study is that it included only white people and most of the participants were male. Results might be different for women or for people from other racial or ethnic groups.
Multiple Measurements May Be Needed
Even so, the findings suggest that patients may need multiple blood pressure measurements seated and standing to better identify individuals who have an increased risk for heart attacks and strokes, particularly among younger adults. After adjusting for average blood pressure taken over 24 hours, an exaggerated blood pressure response to standing remained an independent predictor of adverse heart events or stroke. “The results of the study confirmed our initial hypothesis — a pronounced increase in blood pressure from lying to standing could be prognostically important in young people with high blood pressure,” Dr. Palatini says. “We were rather surprised that even a relatively small increase in standing blood pressure was predictive of major cardiac events in the long run.”
