Diastolic blood pressure, represented by the bottom number in a blood pressure reading, is measured when your heart is at-rest. Georgios Tsivgoulis, from University of Alabama (USA), and colleagues have found that elevated diastolic blood pressure appears to be associated with cognitive impairment in people ages 45 and older.  In their study involving 19,836 black and white individuals from REGARDS (Reasons for Geographic and Racial Differences in Stroke), each 10-point increase over 90 mm Hg was associated with a 7% greater risk of problems with cognition.  The increased risk of cognitive impairment associated with elevated diastolic blood pressure remained after adjusting for several potential confounders, including demographic variables, environmental characteristics, cardiovascular risk factors, depressive symptoms, and use of antihypertensive medications.  The team posits that because elevated diastolic blood pressure can accelerate the normal atrophy of small cerebral arterioles, the process may lead  to formation of ischemic white matter lesions, which could result in cognitive impairment.  The researchers suggest that:   "[I]t's possible that by preventing or treating high blood pressure, we could potentially prevent cognitive impairment."