Mild Exercise Intervention Enhances Hippocampal Neuroplasticity And Memory In Older Adults

PURPOSE: Mild, stress-free exercise enhances hippocampal function, increasing dentate gyrus (DG) neurogenesis and memory in animals. In humans, very light exercise improved pattern separation and DG/CA3 connectivity. This study investigates whether a 3-month mild-exercise (ME) intervention promotes hippocampal neuroplasticity and memory in older adults. METHODS: Forty-five older adults were randomly assigned to either a ME group (n = 24) and control (n = 21) group. The ME group received 3 months of mild cycle exercise intervention (3 sessions/week, 30-50 min/session). The control group maintained daily routines. Pre- and post-intervention assessments included neuropsychological tests, a mnemonic discrimination task, and high-resolution structural MRI. RESULTS: A 3-month ME intervention improved memory and hippocampal function in older adults. The ME group showed significant increases in RAVLT long-term recall, reflecting hippocampal-dependent processes. In the mnemonic discrimination task, Lure Discrimination Index (LDI) scores improved significantly under both lure low and lure all conditions, indicating enhanced pattern separation. Structural MRI revealed increased DG/CA3 volumes, which positively correlated with improvements in RAVLT long-term recall and LDI scores. CONCLUSIONS: These findings indicate that a 3-month mild exercise intervention enhances hippocampal neuroplasticity, leading to improved memory performance. This suggests that mild exercise could be a promising strategy for promoting cognitive health in older adults.