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Aim: The aim of the current study was to assess whether executive function and prefrontal oxygenation are dependent on fitness level and age in older adults., Methods: Twenty-four healthy males aged between 55 and 69 years old were recruited for this study. They were stratified by age, leading to the creation of two groups: 55-60 years old and 61-69 years old. A median split based on CRF created higher- and lower-fit categories of participants. Cerebral oxygenation was assessed using functional near-infrared spectroscopy (fNIRS) during a computerized Stroop task. Accuracy (% of correct responses) and reaction times (ms) were used as behavioural indicators of cognitive performances. Changes in oxygenated (∆[HbO2]) and deoxygenated (∆[HHb]) hemoglobin were measured to capture neural changes. Repeated measures ANOVAs (CRF × Age × Stroop conditions) were performed to test the null hypothesis of an absence of interaction between CRF, Age and executive performance., Results: We also found an interaction between CRF and age on reaction times (p = .001), in which higher fitness levels were related to faster reaction times in the 61-69 year olds but not in the 55-60 year olds. Regarding ΔHHb, the ANOVA revealed a main effect of CRF in the right PFC (p = .04), in which higher-fit participants had a greater Δ[HHb] than the lower-fit (d = 1.5). We also found fitness by age interaction for Δ[HHb] in the right PFC (p = .04)., Conclusion: Our results support the positive association of CRF on cerebral oxygenation and Stroop performance in healthy older males. They indicated that high-fit individuals performed better in the 61-69 year olds group, but not in the 55-60 years old group. We also observed a greater PFC oxygenation change (as measured by Δ[HHb]) in the high-fit individuals., (Copyright © 2021. Published by Elsevier Inc.)

Introduction : Many studies have reported that regular physical activity is positively associated with cognitive performance and more selectively with executive functions. However, some studies reported that the association of physical activity on executive performance in younger adults was not as clearly established when compared to studies with older adults. Among the many physiological mechanisms that may influence cognitive functioning, prefrontal (PFC) oxygenation seems to play a major role. The aim of the current study was to assess whether executive function and prefrontal oxygenation are dependent on physical activity levels (active versus inactive) in healthy young males. Methods : Fifty-six healthy young males (22.1 ± 2.4 years) were classified as active (n = 26) or inactive (n = 30) according to the recommendations made by the World Health Organization (WHO) and using the Global Physical Activity Questionnaire (GPAQ). Bilateral PFC oxygenation was assessed using functional near-infrared spectroscopy (fNIRS) during a computerized Stroop task (which included naming, inhibition, and switching conditions). Accuracy (% of correct responses) and reaction times (ms) were used as behavioural indicators of cognitive performances. Changes in oxygenated (∆HbO 2 ) and deoxygenated (∆HHb) hemoglobin were measured to capture neural changes. Several two-way repeated measures ANOVAs (Physical activity level x Stroop conditions) were performed to test the null hypothesis of an absence of interaction between physical activity level and executive performance in prefrontal oxygenation. Results : The analysis revealed an interaction between physical activity level and Stroop conditions on reaction time ( p = 0.04; ES = 0.7) in which physical activity level had a moderate effect on reaction time in the switching condition ( p = 0.02; ES = 0.8) but not in naming and inhibition conditions. At the neural level, a significant interaction between physical activity level and prefrontal oxygenation was found. Physical activity level had a large effect on ΔHbO 2 in the switching condition in the right PFC ( p = 0.04; ES = 0.8) and left PFC ( p = 0.02; ES = 0.96), but not in other conditions. A large physical activity level effect was also found on ΔHHb in the inhibition condition in the right PFC ( p < 0.01; ES = 0.9), but not in the left PFC or other conditions. Conclusion : The results of this cross-sectional study indicate that active young males performed better in executive tasks than their inactive counterparts and had a larger change in oxygenation in the PFC during these most complex conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

This study aimed to evaluate the effects of cardiorespiratory fitness (CRF) and mean arterial pressure (MAP) on the prefrontal cortex (PFC) oxygenation and dual-task performance in healthy young males. Changes in the concentration of oxygenated (ΔHbO 2 ) and deoxygenated hemoglobin (ΔHHb) in the right and left PFC were examined during a cognitive auditory 2-back task. Cognitive performance (2-back task's accuracy) and walking motor performances were measured in single-tasks (single motor and single cognitive) and dual-task (2-back task + walking). Thirty-six young males were ranked according to their V˙O 2 peak. The second tertile was excluded to generate two groups of different CRF (high fit group: n = 12 and V˙O 2 peak = 56.0 ± 6.7 ml kg -1  min -1 ; low-fit group: n = 12 and V˙O 2 peak = 36.7 ± 4.1 ml kg -1  min -1 ). The CRF groups were further split into two subgroups according to 24-h MAP (higher-MAP, lower-MAP). Two-way ANOVA (CRF x n-back conditions) revealed a significant interaction between the CRF and cognitive task condition on 2-back accuracy (p =  .007) and a main effect of CRF on ⊗HHb in the right and left PFC (p < .05). These results suggest that in healthy young males: 1) for CRF, only low-fit individuals demonstrate dual-task costs in accuracy (Dual < Single), and 2) that in comparison to the low-fit group, the high fit-group demonstrated greater changes in PFC oxygenation in ΔHHb, but not ΔHbO 2 ., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)