"Mind-Muscle Connections": Differential Associations Between Handgrip and Upper Body Strength With Cognitive Function in Young and Middle-Aged Adults.

The relationship between muscle strength and cognition is widely studied in older adults; however, understanding this association at younger ages may help detect markers of early cognitive changes and inform future interventions. Accordingly, we aimed to identify relationships between handgrip, whole-body, upper body, and lower body strength and cognitive functions. A total of 112 adults (aged 18-50 years) completed comprehensive measures of muscle strength, aerobic capacity, body composition, and cognitive function. Hierarchical linear regressions revealed that individuals with stronger handgrip had better mental rotation performance (standardized β = 0.39); those with greater upper body strength had superior recognition (standardized β = 0.52) and pattern separation abilities (standardized β = 0.39), but whole- and lower body strength were not associated. Results demonstrate the unique relationship between upper body strength and aspects of cognitive function, in addition to differential associations of upper body and handgrip strength with encoding, retrieval, and spatial skills. The current findings establish an association between strength and cognitive function earlier than previously thought.