About the Relation of Physical Activity Parameters to Brain Cortical Thickness and Brain Age

Background Physical activity or inactivity shapes the human body in an impressive manner. But evidence about the consequences on our brain is still under investigation. Measurement of physical activity is a complex endeavour and has yet mainly been done with self-reported questionnaires in neuroimaging studies. As an advancement, objective data acquisition with accelerometry is implemented and well-recognized in the PA field. This study sought to combine PA analysis and brain assessment with MRI to find patterns of brain alteration while taking age and sex as a cofactor into account. Methods From the NAKO dataset a total of 578 participants provided conclusive data including brain MRI, self-reported PA, and accelerometry-based PA. T1-weighted brain MRI scans were used to quantify grey matter (volume and) cortical thickness with the aid of the computational anatomy toolbox (CAT12). PA was condensed to two parameters: self-reported hours of activity multiplied by intensity, measured in metabolic equivalent of task (MET); second, the average rate of intensity in MET that was measured by accelerometry. Regional deviation in cortical thickness from an average brain template was observed including age and sex as a cofactor. Results Self-reported questionnaire and accelerometry data were positively correlated with each other. The total amount of self-reported MET-minutes per week was related to higher cortical thickness in right inferior temporal gyrus region for participants between 40-49y of age. For accelerometry-based MET-rate an inverse correlation in the right parahippocampal gyrus was found, when corrected for age and sex. When looking at sex-separated accelerometry data, physically active female participants exposed higher cortical thickness in right postcentral gyrus and right superior frontal gyrus. Conclusion The study underpins existing literature of PA related alteration of cortical thickness in multiple brain regions. The comprehensive NAKO dataset expands evidence by including participants for the whole adulthood age spectrum. PA recording has improved by means of objective measurement. However, limitations for PA acquisition need regard in this study.