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Frailty is characterized by an increased vulnerability to adverse health events. Executive function impairment is an early sign of progression towards cognitive impairments. Whether frailty is associated with executive function and the associated mechanisms are unclear. We test the hypothesis that higher frailty is associated with worse executive function (Trail Making Test) and if aerobic fitness, prefrontal cortex oxygenation (ΔO2Hb), or middle-cerebral artery velocity (MCAv) impact this association. Forty-one (38 females) cognitively health older adults (70.1 ± 6.3 years) completed a Trail task and 6-min walk test. Prefrontal cortex oxygenation was measured during the Trail task (via functional near-infrared spectroscopy) and MCAv in a sub-sample (n=26, via transcranial Doppler). A 35-item frailty index was used. Frailty was independently, non-linearly related to trail B performance (Frailty2: β=1927 [95% CI: 321–3533], p = 0.02), with the model explaining 22% of the variance of trail B time (p = 0.02). Aerobic fitness was an independent predictor of trail B (β=−0.05 [95% CI: −0.10–0.004], p = 0.04), but age and ΔO2Hb were not (both, p > 0.78). Frailty was positively associated with the difference between trails B and A (β=105 [95% CI: 24–186], p = 0.01). Frailty was also associated with a higher peak MCAv (ρ = 0.40, p = 0.04), but lower ΔO2Hb-peakMCAv ratio (ρ = −0.44, p = 0.02). Higher frailty levels are associated to worse Trail times after controlling for age, aerobic fitness, and prefrontal oxygenation. High frailty level may disproportionately predispose older adults to challenges performing executive function tasks that may manifest early as a compensatory higher MCAv despite worse executive function, and indicate a greater risk of progressing to cognitive impairment. [ABSTRACT FROM AUTHOR]

International physical activity guidelines recommend that older adults accumulate 150 min/week of moderate-vigorous physical activity (MVPA). It is unclear whether meeting this recommendation is associated with better higher-order cognitive functions and if so, what are the neurophysiological mechanisms responsible for such a relationship. We tested the hypothesis that meeting MVPA guidelines is associated with better executive function in older adults, and explored if greater increases in prefrontal cortex oxygenation are implicated. Older adults who did (active, n = 19; 251 ± 79 min/week) or who did not (inactive, n = 16; 89 ± 33 min/week) achieve activity guidelines were compared. Executive function was determined via a computerized Stroop task while changes in left prefrontal cortex oxygenation (ΔO2Hb) were measured with functional near-infrared spectroscopy. Aerobic fitness ( VO ˙ 2peak) was determined using a graded, maximal cycle ergometry test. MVPA and sedentary time were objectively assessed over 5 days. Both groups had similar (both, P > 0.11) levels of aerobic fitness (24.9 ± 8.9 vs. 20.9 ± 5.6 ml/kg/min) and sedentary time (529 ± 60 vs. 571 ± 90 min/day). The active group had faster reaction times (1193 ± 230 vs. 1377 ± 239 ms, P < 0.001) and greater increases in prefrontal cortex ΔO2Hb (9.4 ± 5.6 a.u vs. 5.8 ± 3.4 a.u, P = 0.04) during the most executively demanding Stroop condition than the Inactive group. Weekly MVPA was negatively correlated to executive function reaction times (r = − 0.37, P = 0.03) but positively correlated to the ΔO2Hb responses (r = 0.39. P = 0.02) during the executive task. In older adults, meeting MVPA guidelines is associated with better executive function and larger increases in cerebral oxygenation among older adults. [ABSTRACT FROM AUTHOR]

Background: Studies have shown a positive relationship between cardiorespiratory fitness (CRF) and executive functioning in older adults. Although this relationship has been well established, there seems to be a gap in the literature on the role of sex differences concerning CRF and executive functions. The current study aimed to assess the effect of sex in the relationship between CRF and cognition in older adults by stratifying the results to examine effects in males and females., Methods: Ninety-six older adults (61 females) gave their written, informed consent to participate in this cross-sectional study. All participants underwent a maximal continuous graded exercise test on a cycle ergometer to assess their maximal oxygen uptake (VO2max) and a computerized Stroop task (naming, inhibition, and switching) to assess their executive functions. According to VO2max test results and the American College of Sports Medicine's guidelines, females and males were classified into higher-fit and lower-fit groups. A general linear model and estimated marginal means analyses were applied., Results: Results showed no significant differences in the naming, inhibition and switching performance tests between male and female older adults (P>0.05)., Conclusions: Based on the observed positive relationship between CRF and executive functioning, the data of the current study supports the idea that aerobic exercise, which typically increases CRF, is well-situated to improve executive functioning in older adults, irrespective of sex.