Rising energetic cost of walking predicts cognitive impairment

The energetic cost of walking increases with age and is linked to physical function impairment, but its relation to cognitive impairment is unknown.

A total of 687 initially cognitively normal older adults (mean age 74.0 ± 7.2 years, 52% women) underwent repeated walking energy expenditure assessments (V̇O₂) and adjudicated cognitive diagnoses over 7.6 ± 3.8 years. We examined (1) trajectories in the energetic cost of walking prior to any clinical diagnosis of cognitive impairment, comparing adults who later developed cognitive impairment versus those who did not, and (2) the baseline energetic cost and future risk of cognitive impairment using linear mixed-effects and Cox regression models.

Ninety-one participants (13%) progressed to cognitive impairment. Progressors exhibited a steeper increase in energetic cost than non-progressors (B = 0.13; p = 0.003). Higher baseline cost predicted impairment among adults ≥75 years (hazard ratio [HR] = 1.1, 95% confidence interval [CI] = 1.00 to 1.20, p = 0.039), but not those aged 65 to 74 (HR = 0.91, 95% CI = 0.81 to 1.01, p = 0.089).

Walking efficiency provides a physiological link between mobility and cognitive health; preserving efficiency may reduce risk of Alzheimer's disease and related dementias.