The Relation of Having Experienced a Fall in the Past to Lower Cognitive Functioning in Old Age Is Mediated via Less Physical Activity Engagement as Cognitive Reserve Contributor

SIMPLE SUMMARY: Experiencing a fall in old age represents a critical life event affecting physical and cognitive health and the ability to engage in physical activities and exercise. This is crucial since physical activity engagement contributes to the accumulation of the so-called cognitive reserve relevant for maintaining cognitive health at old age. The goal of our study was to investigate whether the relationship between having experienced a fall and lower cognitive functioning can be explained by hampered physical activity engagement. Confirming this idea, our findings demonstrated that experiencing a fall at an older age hinders sufficient physical activity engagement and thereby impedes cognitive reserve accumulation, resulting in lower cognitive functioning outcomes. Consequently, our study suggests that at old age, the prevention of falls and related accidents is not only crucial to avoid injuries and preserve physical health, but it is also essential for maintaining one’s ability to engage in physical activities and exercises and, consequently, for preserving cognitive health in later life. ABSTRACT: Physical activity and exercise contribute to the accumulation of cognitive reserve, which is instrumental for preserving cognitive health in old age. In a large sample of 701 older adults (mean age = 70.36 years), we investigated whether the relationship between having experienced a fall in the past and lower performance in cognitive functioning was mediated via less physical activity engagement as a cognitive reserve contributor. General cognition was assessed using the mini-mental state examination (MMSE), long-term memory using a word-pair delayed recall test and working memory using a backward digit-span test. In face-to-face interviews, individuals reported information on falls during the past 12 months and their habitual physical activity engagement. Our analyses demonstrated that the relationship between having experienced a fall in the past and lower performance in the cognitive functioning measures was partly mediated (by 16.3% for general cognition, 30.6% for long-term memory, and 33.1% for working memory, respectively) via less physical activity engagement. In conclusion, we suggest as a core bio-psychological mechanism that experiencing a fall at an older age is a critical life event that hinders sufficient physical activity engagement and thereby impedes cognitive reserve build-up, resulting in lower cognitive functioning outcomes.