When doctors tell patients with high blood pressure to get some exercise, most of them listen - yet too few doctors are doing so, a new study suggests.

Using data from a government health survey, researchers found that only one-third of U.S. adults with high blood pressure said their doctors had counseled them on getting regular exercise.

But of those who did get such advice, 71 percent followed it - and had lower blood pressure than their counterparts who remained inactive, the investigators report in the journal Ethnicity & Disease.

“The blood pressure reduction was ... unexpected, as this was not a trial to determine whether exercise would reduce blood pressure,” lead researcher Dr. Josiah Halm, of the University of Wisconsin School of Medicine, said in a statement.

Doctors, he said, should be encouraging exercise as a way to manage high blood pressure, even if they think they do not have time for such a conversation.

“Clinicians will always decry not having enough time to counsel, but a method of using a prescription pad with exercise recommendations as suggested in the study will help solve this quandary,” Halm said.

The findings are based on a federal health survey that included 4,686 U.S. adults with high blood pressure. Of these participants, 33 percent said their doctor had told them to exercise regularly to help lower their blood pressure.

Among people who’d received this advice, Halm’s team found, 71 percent said they’d heeded it - and their blood pressure was several points lower, on average, than men and women who had not taken up exercise.

This does not prove that exercise was responsible for the lower blood pressure. However, the researchers point out, other studies have found that exercise does cut elevated blood pressure, even in the absence of weight loss.

Halm and his colleagues suggest that doctors think about exercise as a prescription, and actually write down on a prescription pad the type, intensity and duration of exercise each patient should try.

SOURCE: Ethnicity & Disease, Summer 2008.