by Michelle Rizzi

Last Updated: 2008-06-20 14:56:59 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Elevated diastolic blood pressure measured during low-level exercise or recovery predicts an increased risk of cardiovascular disease, according to researchers.

"Exaggerated systolic blood pressure augmentation with exercise has been associated with impaired endothelial function and cardiovascular risk," lead investigator Dr. Gregory Lewis, of Harvard Medical School, Boston, and colleagues write in the June issue of the American Journal of Cardiology.

"However, previous studies were largely restricted to men, did not evaluate diastolic blood pressure, and focused on peak exercise measures, which are influenced by effort and fitness level."

To better understand these relationships, Dr. Lewis’s group examined the association between blood pressure responses during or immediately after low-level exercise and the long-term risk of incident cardiovascular disease (CVD) in 3045 participants of the Framingham Heart Study. More than half (53%) were women, the mean age was 43 years old, and the study participants were followed for 20 years.

During follow-up, 240 patients experienced a first cardiovascular event and 181 experienced a first coronary heart disease event. The results of age- and sex-adjusted analyses revealed an association between exercise systolic and diastolic blood pressure and incident CVD (hazard ratios for top quintiles 1.55 and 1.77 compared with lower four quintiles).

After adjustment for blood pressure at rest and conventional risk factors, diastolic blood pressure during exercise remained a significant predictor of incident CVD (HR 1.41, p = 0.04), but exercise systolic blood pressure did not.

A similar relationship was observed between recovery blood pressure and incident cardiovascular events, with only diastolic blood pressure predictive of incident CVD (HR 1.53, p = 0.02).

"The ability of modest exercise to predict outcomes may be particularly useful in interpreting exercise tolerance test results in patients unable to sustain a high level of exercise," Dr. Lewis said in an interview with Reuters Health. "In addition, the amount of exercise performed in this study is indicative of levels of daily physical activity, and therefore blood pressure measurements from our study reflect blood pressure to which patients are exposed on a daily basis."

"More work is needed in determining the mechanisms by which blood pressure increases disproportionately in some patients during exercise and in determining approaches to prevent the development of high blood pressures in response to physical activity," Dr. Lewis added.

Am J Cardiol 2008;101:1614-1620.

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