Rising energetic cost of walking predicts cognitive impairment.

Participants who later developed cognitive impairment exhibited a steeper increase in energetic cost of walking than those who did not progress.

• B = 0.13; p = 0.003 for the difference in trajectories between progressors and non-progressors
• 91 participants (13%) progressed to cognitive impairment out of 687 initially cognitively normal older adults
• Trajectories were examined prior to any clinical diagnosis of cognitive impairment
• Linear mixed-effects models were used to examine energetic cost trajectories

Higher baseline energetic cost of walking predicted future cognitive impairment in adults aged 75 years and older, but not in those aged 65 to 74.

• In adults ≥75 years: HR = 1.1, 95% CI = 1.00 to 1.20, p = 0.039
• In adults aged 65 to 74: HR = 0.91, 95% CI = 0.81 to 1.01, p = 0.089
• Cox regression models were used to assess baseline energetic cost and future risk of cognitive impairment
• The age-stratified difference suggests the predictive value of walking energetic cost may be age-dependent

The study followed 687 initially cognitively normal older adults over a mean follow-up period of approximately 7.6 years with repeated walking energy expenditure assessments.

• Mean age at baseline was 74.0 ± 7.2 years; 52% were women
• Follow-up duration was 7.6 ± 3.8 years
• Walking energy expenditure was measured as VO2 during walking assessments
• Cognitive diagnoses were adjudicated over the follow-up period

The energetic cost of walking increases with age and is linked to physical function impairment, and this study establishes a previously unknown relation to cognitive impairment.

• Prior research had linked rising energetic cost of walking to physical function impairment but not to cognitive outcomes
• Walking efficiency is proposed to provide a physiological link between mobility and cognitive health
• Preserving walking efficiency may reduce risk of Alzheimer's disease and related dementias