Changes in cognition and mortality in relation to exercise in late life: a population based study

Area of Science:

• Gerontology
• Cognitive Neuroscience
• Public Health

Background:

• Cognitive decline is common with aging, but individual variability exists, including potential for improvement.
• The relationship between physical activity, cognitive change, and mortality in older adults requires further investigation.
• A key question is whether increased longevity due to exercise could paradoxically increase dementia risk.

Purpose of the Study:

• To investigate the association between exercise frequency and intensity with cognitive change over time in older adults.
• To examine the relationship between exercise habits and mortality risk in the elderly population.
• To determine if exercise's benefits on cognition and mortality are modified by baseline cognitive status.

Main Methods:

• Utilized data from the Canadian Study of Health and Aging (CSHA) with 8403 participants.
• Employed a parametric Markov chain model to estimate probabilities of cognitive improvement, decline, and death.
• Adjusted analyses for age and education, categorizing participants into high exercisers (≥3 times/week, ≥walking intensity) and low/no exercisers.

Main Results:

• High exercisers demonstrated significantly higher rates of stable or improved cognition (42.3%) compared to low/no exercisers (27.8%) over 5 years.
• Cognitive decline was more prevalent in high exercisers, but the difference between groups was modest.
• Non-exercisers had a substantially higher mortality rate (37.5%) compared to exercisers (18.3%).
• The mortality benefit of exercise was most pronounced in individuals with the highest baseline cognitive function.

Conclusions:

• Exercise is strongly associated with cognitive improvement in older adults.
• The majority of exercise's mortality benefit is observed in those with higher cognitive function.
• Overall, exercise is expected to enhance cognition at the population level, even with increased lifespan.