Among 58 sedentary, cognitively unimpaired older adults (mean age 70.7 years, 84.5% female), greater 6-minute walk test (6MWT) distance was the only physical function measure to survive false discovery rate correction, associating significantly with better episodic memory performance (β=0.49, p=0.028). Handgrip strength and chair stand performance showed no cognitive associations. Timed-up-and-go and gait speed trended toward global cognition and attentional inhibition links but did not survive correction.
The finding reinforces a growing body of evidence distinguishing locomotor endurance from static strength as the more cognitively sensitive physical marker in aging. Episodic memory — among the earliest faculties to decline in Alzheimer's trajectories — shares neural substrates with hippocampal-dependent spatial navigation, which sustained walking strongly recruits. This specificity is theoretically coherent and clinically intriguing, suggesting 6MWT could serve as a simple, low-cost cognitive screening adjunct in primary care settings for older sedentary adults.
However, the limitations here are substantial. With only 58 participants (overwhelmingly female), the study is severely underpowered for domain-specific subgroup analyses, and the cross-sectional design prevents any causal inference. The female-skewed sample limits generalizability to men. Importantly, this is a preprint posted on medRxiv and has not yet undergone peer review — findings should be treated as hypothesis-generating. Larger longitudinal trials with balanced demographics are needed before clinical recommendations could be considered. As an exploratory signal, though, the locomotor-cognition specificity hypothesis merits serious follow-up.
