News Release

Blood pressure during sleep may be important too

Peer-Reviewed Publication

Mayo Clinic

Blood pressure levels differ greatly from person to person. We know this based on blood pressure readings taken during people's waking hours. But what happens when people are sleeping?

It turns out that there are equally large differences in blood pressure levels among people during the nighttime, according to a Mayo Clinic study.

The Mayo researchers put ambulatory blood pressure monitors on 240 healthy people (all but two had normal blood pressure) and obtained blood pressure readings every 10 minutes for 20 consecutive hours.

The somewhat surprising finding was that differences in blood pressure levels among the participants in the study were as great or greater when they were sleeping as when they were busy with daytime activities.

"We know that differences in blood pressure levels among people during the daytime are associated with differences in the risk for heart disease, renal injury and stroke," says Gary Schwartz, M.D., a Mayo Clinic hypertension specialist and lead investigator of the study. "It has traditionally been thought that blood pressure declines to safe levels in most people during sleep and that nighttime is a period of minor differences in blood pressure levels among people.

"The implication of our finding is that differences in blood pressure levels among people at night may make an additional contribution to people's risk of heart disease, renal injury and stroke," says Dr. Schwartz.

He says that for most people with high blood pressure, medications probably adequately control blood pressure during both day and night. "However this study suggests that we may need to measure blood pressure levels at night in some people in order to assure adequate treatment is being given. Further research is needed to determine what levels of blood pressure at night are unsafe and what treatments are most effective to lower blood pressure during this period."

The study appeared in the American Journal of Hypertension.

###

Mike O'Hara
507-284-9522 (days)
507-284-2511 (evenings)
e-mail: newsbureau@mayo.edu


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.