Higher Fitness Levels Influence Association Between Cognition And Mobility In Older Adults With Hypertension And Dementia Risk

Abstract

Higher levels of fitness are associated with preserved cognitive function in older adults. Preserved cognition is linked to better mobility and reduced risk of falls. However, it remains to be explored whether cardiovascular fitness (CF) influences the link between cognition and mobility in individuals with cardiovascular disease burden and risk of dementia. PURPOSE: We explored whether CF influences the relationship between cognition and mobility in older adults with hypertension and subjective cognitive decline. These individuals are at higher risk of dementia due to cardiovascular disease burden and early sings of cognitive impairment. METHODS: Older adults (n = 118, age 70.1 (SD = 6.7) years, 62% males) underwent CF assessment (Bruce protocol treadmill stress test) and were grouped based on Bruce protocol stage completion into low (stage 1 [n=31]), average (stage 2 [n=57]), and high (stage ≥3 [n=30]) CF groups. Cognition was measured via the Cambridge Brain Sciences cognitive battery; mobility (usual and dual-task gait [naming animals]) was measured using the GAITRite walkway system. We conduced hierarchical regression models adjusting for sex, age and years of education to determine whether CF modulated association between cognition and mobility. RESULTS: For usual gait, cognition was positively associated with gait velocity in high CF (Change statistics: F(1,25)=14.3, p=.001, R2=.35,), as well as step length in high CF (F(1,25)=10.8, p=.003, R2 =.27) and average CF (F(1,50)=4.4, p=.04, R2 =.08,), and gait variability in average CF (F(1,48)=9.8, p=.003, R2=.17). For dual-task gait, cognition was positively associated with gait velocity in both high CF (F(1,25)=9.15, p=.006, R2=.26) and average CF (F(1,49)=5.8, p=.02, R2 =.10), as well as step length in both high CF group (F(1,25)=7.2, p=.01, R2=.21) and average CF group (F(1,49)=7.2, p=.01, R2 =.13). CONCLUSIONS: Cognition was positively associated with mobility outcomes in individuals with average and high CF, while no associations were seen in those with low CF. These findings suggest that the protective effects of cognition on mobility (e.g., reduced falls risk and prolonged independence) may be hindered by low CF in older adults with hypertension.