The Impact of Physical Exercise on Working Memory in Elderly People With Mild Cognitive Impairment

Age-related cognitive decline has evolved into a global public health concern, with deteriorated executive function serving as its predominant manifestation. Working memory, a vital component of executive function, refers to a capacity-limited system that temporarily stores and manipulates information during sophisticated cognitive processes such as language comprehension, learning, and reasoning. It constitutes the core of general cognitive functioning and underpins daily functional performance.

The prefrontal cortex is a pivotal brain region subserving working memory and is highly vulnerable to pathological aging. Advancing age triggers prefrontal cortical atrophy and reduced synaptic density, which in turn induces working memory impairment. Consistently, existing evidence identifies working memory as one of the cognitive domains most susceptible to aging and among the first functions compromised in neurodegenerative disorders including Alzheimer's disease.

As a non-pharmacological strategy, physical exercise intervention has been validated to exert favorable effects on cognitive improvement. Both aerobic and resistance training effectively ameliorate working memory; nevertheless, head-to-head evidence comparing their intervention efficacy among older adults with mild cognitive impairment (MCI) remains scarce, particularly regarding underlying neurophysiological mechanisms. This study aims to explore the impacts of physical training on working memory in older women living with MCI.

Accordingly, the present study aimed to investigate the effects of both a single exercise session and a 12-week intervention on upper- and lower-limb muscle strength and working memory in older women with MCI. In addition, we sought to examine the statistical associations between changes in muscle strength and working memory, with particular attention to the potential mediating role of muscle strength changes. Previous studies have suggested that interventions targeting muscle strength and physical function in middle-aged and older adults are commonly implemented over 12-52 weeks at a frequency of two to three sessions per week, whereas exercise interventions targeting cognitive function in older adults are often conducted over 12-24 weeks at a similar frequency. Based on this evidence, together with feasibility considerations in residential care settings, we adopted a 12-week intervention delivered three times per week. This study contributes to the literature by integrating both acute and chronic effects within a single randomized controlled framework and by exploring the muscle strength-cognition pathway as a potential explanatory mechanism for exercise-related cognitive benefits.