Polysubstance use disorders among US adults.

Cognitive function encompasses multiple domains, including attention, memory, language, visuospatial abilities, and executive functions. These domains are critical psychological resources for sustaining work performance, learning capacity, and daily living activities (,). Enhanced cognitive abilities help delay age-related decline and reduce the risk of neurodegenerative diseases (). Most studies on cognitive function have focused on older adults or individuals with cognitive impairments. However, emerging evidence indicates that cognitive changes can begin subtly in early or middle adulthood (), even among healthy individuals (). Therefore, maintaining and assessing cognitive function in healthy adults has become increasingly important (). Current cognitive assessments, such as the N-BACK task, Trail Making Test (TMT) (), and Mini-Mental State Examination, are mainly intended for screening or diagnostic purposes. These assessments are subject to various limitations, including the testing environment, learning effects (,), mental fatigue, the need for administration by trained professionals (), and limited ecological validity (). Consequently, they are not suitable for routine or continuous monitoring in the general population. Thus, there is a need to develop objective and continuous cognitive monitoring tools for healthy adults (). These tools would enable early detection of cognitive changes, support personalized health promotion strategies, and advance preventive health management systems (). The conceptual foundation of the “Cardiorespiratory Fitness (CRF) Hypothesis” originates from Dustman et al. (), who proposed that enhanced aerobic capacity (i.e., CRF, a key indicator of overall physical fitness) can improve cerebral hemodynamics and neuroplasticity, thereby influencing cognitive function (,). Subsequently, accumulating evidence suggests that brain structural and functional changes may partly mediate the relationship between cardiorespiratory fitness and cognitive performance (–). Furthermore, exercise interventions that promote CRF have been shown to yield beneficial effects on cognitive performance (,).