Linking the Heart with the Brain Through Physical Activity
Description
This study aims to better understand the mechanisms by which cardiac rehabilitation (CR) may influence cognitive function. Compared with the rest of Canada, cardiovascular disease (CVD) and its risk factors have been shown to be more prevalent in Atlantic Canada1. Some of the highest CVD mortality rates in Canada were observed in New Brunswick (NB). Beyond CVD, there is evidence that hypertension-related end-organ cardiac damage can increase the risk for cognitive decline and dementia. More precisely, CVD and its risk factors have been associated with the loss of gray matter in large areas of the brain, including those with a significant role in cognitive function and behaviour, such as the executive functions located in the prefrontal cortex. However, CVD-related cognitive impairments may potentially be reversible since in addition to reducing the risk of cardiovascular events and hospitalisation, and improving physical condition and quality of life, it was shown that participation in a cardiac rehabilitation (CR) program relates to improvements in cognitive functions. Systematic reviews have shown that the most consistent cognition-related improvements after a 12-week CR program were seen in the areas of Executive Function, Memory, and Attention. Nevertheless, it is unclear through which physiological mechanisms these improvements occur. A recent study investigating the effects of a 12-weeks CR on cognitive performance and cerebral oxygenation (measured with Near Infrared Spectroscopy) has shown that improvements in cognition after the CR program were correlated with improvements in neural efficiency and increases in prefrontal cortex cerebral oxygenation.In addition, prefrontal cortex oxygenation reflects the extraction of oxygen from local blood flow, whereas it is unclear whether the delivery of blood to the brain is implicated in the brain’s oxygen extraction process. In patients with CVD, resting middle cerebral artery velocity (MCAv; surrogate of cerebral blood flow) has been demonstrated to be highly correlated with executive function9. Altogether, these previous studies present segmented hypotheses of how CR (i.e., physical exercise) contribute to improving cognitive function among patients with CVD. As a result, we currently only have a fragmented knowledge of the relationship between CVD, executive function, and CR. A more holistic comprehension of the neurophysiological mechanisms underpinning these relationships would allow for an insight into the different relative contributions of each cerebrovascular process underlying CVD-related brain changes associated with physical activity. Studying these mechanisms will help healthcare professionals optimize physical activity interventions in a CR setting in the hope of attenuating the decrease of physical and cognitive function associated with CVD.
Objectives
Therefore, the objective of this study is to: 1) investigate the relationship between CVD and executive function before and after a 12-weeks CR program, and 2) simultaneously assess the relative contribution of prefrontal oxygenation (oxygen extraction) and MCAv (oxygen delivery) in CR-related changes in executive function among patients with CVD
Team
Principal Investigators : Saïd Mekari and Mathieu Bélanger
Co-Investigators: Nicole Marquis, Monique Dufour Doiron, Pamela Tanguay and Pierre Faivre.
Funding Agencies
This project is supported by: Coeur + AVC N.-B. et RechercheNB.
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