Cardiovascular disease (CVD) in older adults has been associated with varying degrees of cognitive dysfunction. Several mechanisms may explain this association, including impaired cardiovascular reactivity to autonomic nervous system (ANS) signaling. Reduced heart rate recovery following a stress test may be considered an indication of impaired ANS function (i.e., reduced parasympathetic activity). Participants were 47 older adults (53–83 years) who underwent a treadmill stress test and were administered a comprehensive neuropsychological battery upon entry to phase II cardiac rehabilitation. Reduced parasympathetic activity was associated with impaired cognitive performance on a measure of global cognitive function and on tasks of speeded executive function and confrontation naming. These relationships suggest that changes in autonomic function may be mechanistically related to the impaired cognitive function prevalent in CVD patients. 1. Introduction Cardiovascular disease (CVD) is associated with varying degrees of cognitive impairment, ranging from minimal difficulties (“brain at risk stage”) to dementia [1–4] and is associated with cognitive decline above and beyond the normal aging process [5]. Impaired cognitive function is observed in persons with CVD, even in the absence of major cardiac events [6]. Older adults with CVD frequently report experiencing significant cognitive dysfunction in everyday life and men with CVD demonstrate a reduction in cognitive function equivalent to approximately four to five years of additional age [7, 8]. These findings are in addition to the known associated between CVD and severe neurological conditions like stroke and Alzheimer’s disease [9, 10]. Several pathophysiological mechanisms associated with CVD contribute to the observed cognitive dysfunction in this population. For example, systemic hypoperfusion is common and associated with reduced cognitive test performance [11–13]. Similarly, CVD is associated with development of white matter disease [14], pathological changes to blood vessels [15], and inflammatory processes [16], each of which are known to adversely impact cognitive function. Recent work implicates disrupted autonomic nervous system (ANS) signaling as another potential mechanism for the cognitive impairment, as both blood pressure variability (e.g., standard deviation of systolic blood pressure) and heart rate variability have been linked to neurocognitive outcome in persons with CVD [17–19]. Such findings suggest that other, more easily obtained ANS indices may also be associated with reduced
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