Redefining Hypotension in Older Adults: Implications for the Prevention of Age Related Cognitive Decline

Abstract

Chronically low blood pressure in older adults is associated with significantly increased long-term risks of dementia and all-cause mortality risk. Yet low blood pressure is generally not treated until an individual begins to experience the acute symptoms arising from very low cerebral perfusion. However, these acute symptoms, such as dizziness, balance difficulty, syncope, increased fall occurrence, vision impairment, and nausea, begin to occur only at very low blood pressure levels, such that mean arterial pressure levels as low as 65mmHg are often considered to be of limited concern. If the long-term consequences of chronic low blood pressure are to be prevented, an alternative approach to defining what constitutes too low a blood pressure for older adults, i.e. hypotension, will be required. Cognitive aging is a significant health concern for many older adults as it has significant impact on quality of life, and is widely considered a precursor to dementia. Here, we utilize an FDA cleared computer aided cognitive assessment tool to identify the relationship between resting brachial blood pressure in the upright seated position, and cognitive function in a convenience sample of independently living older adult men and women. We observed that resting diastolic blood pressure is significantly and positively correlated with cognitive function in adults over the age of 60 years. Specifically, cognitive performance was found to be significantly impaired for diastolic blood pressure levels below approximately 80 mmHg. Diastolic blood pressures (DBP) below 80 mmHg in older adults have consistently been shown to increase the risk of dementia as well as all-cause mortality, but the influence of below normal DBP on quality of life (QoL) in older adults has not been extensively addressed. The present work shows that adults over age 60, with a DBP below 80 mmHg, are significantly more likely to demonstrate mild to moderate cognitive impairment, and correspondingly, the associated impacts on QoL. These results lead to the suggestion that maintenance of diastolic blood in older adults in the 80-90 mmHg range will not only improve quality of life in this population, but may also provide substantial clinical benefit in terms of preventing, or reversing, age-related cognitive decline.