Beware of Blood Pressure Changes at Night

Osborne said this study “is another signal that we really need to incorporate ambulatory blood pressure monitoring into the evaluation of high blood pressure. If we only see blood pressure during the day, it dramatically reduces our ability to assess overall risk.”

Ambulatory blood pressure monitoring allows doctors to see blood pressure levels over a 24-hour period, according to the American Academy of Family Physicians. Patients are fitted with a blood pressure cuff and sent home with a portable monitor that automatically inflates at regular intervals. The machine also records each blood pressure reading it takes in a day.

The current study included more than 6,300 Japanese adults. Their average age was 69. Almost half were men, and more than three-quarters were on blood pressure lowering medications. The average follow-up time was four years.

During the study, volunteers had 20 daytime and seven nighttime ambulatory blood pressure monitor readings.

So should everyone with high blood pressure get their nighttime blood pressure checked, too?

“The best answer right now is maybe. Keep in mind these were people with some existing cardiovascular disease risk factors [already],” Townsend explained. They were also all Japanese, and the findings might not be generalizable to other populations.

And, though it seems to be slowly changing, reimbursement for ambulatory blood pressure monitoring can be tough to get, Townsend said.

But, he added, “The take-home for me is that there is information available about an individual in their nighttime blood pressure patterns.”

Both Townsend and Osborne said changing the timing of blood pressure medications might help, but there’s not enough data to say for sure if it would. Both said more research is needed.

More information

Want to check your blood pressure at home? Visit Validate BP, a website from the American Medical Association that checks commercially sold blood pressure monitors to make sure they’re effective.

SOURCES: John Osborne, M.D., director, cardiology, State of the Heart Cardiology, Dallas; Raymond Townsend, M.D., American Heart Association, volunteer expert, and professor of medicine and director, hypertension program, University of Pennsylvania