Exercise-Based Cardiac Rehabilitation Improves Cognitive Function Among CVD Patients

Abstract

PURPOSE: To investigate the effects of cardiac rehabilitation (CR) exercise training on cognitive performance and if the changes are associated with alterations in prefrontal cortex (PFC) oxygenation among patients with cardiovascular disease (CVD). METHODS: Twenty (M=15, F=5; 64.8±11.6 yrs) participants from an outpatient CR program were enrolled in the study. Each participant completed a cognitive performance test battery (the NIH Fluid Cognition test battery which measured 5 cognitive constructs) and a submaximal graded treadmill evaluation (a measure of cardiorespiratory capacity) on separate occasions at pre and again upon completion of 18 individualized CR sessions (approximately 6 weeks later). A functional near-infrared spectroscopy (fNIRS) device was used to measure left - and right- PFC (LPFC and RPFC) oxygenation parameters (O2Hb = oxyhemoglobin, HHb = deoxyhemoglobin, tHb = total hemoglobin, Hbdiff = oxyhemoglobin difference) during the NIH Fluid Cognition evaluation. RESULTS: Patients showed improvements in cardiorespiratory capacity (increased by 1.4 METs) and various cognitive constructs (processing speed, attention, executive function, and working memory scores). A significant increase in PFC oxygenation, primarily in the LPFC region, occurred at post-CR test (in four of the five cognitive tests). Correlation analyses revealed negative associations between changes in cognition (executive function (LPFC O2Hb: r = -0.445, p = 0.049; LPFC tHb: r = -0.487, p = .030) and fluid composite score (RPFC Hbdiff: r = -0.467, p = 0.038; LPFC Hbdiff: r = -0.447, p = .048)) and PFC changes. The change in cardiorespiratory capacity was positively associated with the change in working memory score (r = 0.546, p = 0.016). CONCLUSION: CVD patients enrolled in CR showed significant improvements in multiple cognitive domains along with increased cortical activation. The negative associations between cognitive functioning and PFC oxygenation suggest an improved neural efficiency, which is identified as higher cognitive performance for a given (or reduced) amount of cortical activation.