Tracing the path from OCEAN to autonomic balance: The mediating role of cognitive reserve

Aging trajectories vary widely. The Big Five – Neuroticism, Openness, Extraversion, Agreeableness, and Conscientiousness – describe individual differences in behavioral, emotional, and physiological patterns influ- encing health. Heart rate variability (HRV), index of autonomic dynamics, is linked to longevity and cognitive decline in older adults, making it a potential personality-related marker of pathological aging. Inconsistencies in the HRV-personality relationship prompt researchers to consider mediating factors. Cognitive reserve (CR) offers insights, as it is shaped by personality and linked to brain regions underlying HRV. This study investigated the personality-HRV relationship, highlighting CR as a potential mediator. We hy- pothesized that lower CR would be associated to a higher LF/HF ratio, indicating sympathetic dominance and previously linked to poorer cognition, and that personality would contribute to this pattern through CR. Eighty- nine participants over 50 years underwent HRV recording, the CR Index questionnaire, and the Big Five In- ventory administration. As expected, higher LF/HF ratio was associated with lower Openness and CR; CR mediated the relationship between Openness and Neuroticism and LF/HF ratio, suggesting that personality could influence physiological and cognitive health through cognitively stimulating activities. These findings under- score the role of life experiences and individual differences in shaping health, offering insights for prevention and intervention strategies.