The BMJ Group's new study in the British Journal of Sports Medicine demonstrates a substantial association between cardiorespiratory fitness and the maintenance of cognitive ability in older persons. This link is true irrespective of significant risk variables for cognitive decline, such as age and the APOE4 gene, which is typically associated with an elevated risk of Alzheimer's.

The study, which included 648 cognitively healthy participants aged 65 to 80 (average age 69), found that those with stronger cardiorespiratory fitness performed better across multiple cognitive areas. We assessed cardiorespiratory fitness using VO2max, an index of maximum oxygen uptake during exercise, and examined cognitive performance using a battery of neuropsychological tests. These examinations focused on five essential areas of cognitive function: processing speed, working memory, visuospatial processing, episodic memory, and executive function and attentional control, which include skills like planning and organization.

Despite the established unfavorable influence of age and APOE4 gene carriers on cognitive ability, higher levels of cardiorespiratory fitness were consistently associated with improved performance in all areas.

Women made up 71% of the study group, and participants averaged 16 years of schooling. Of the 640 genotyped individuals, 27% were APOE4 carriers, and 15% used beta-blockers for cardiac problems.

The strongest link was found between cardiorespiratory fitness and cognitive performance, especially in the areas of processing speed and executive function/attentional control. This was true for women, people with less education, and people who used beta-blockers.

While this was an observational study, the researchers provided several explanations for the reported advantages of cardiorespiratory fitness in cognition. Improved aerobic fitness may increase cerebral blood flow, lower oxidative stress, boost neurogenesis, and strengthen neurotransmitter systems. It may also improve the structural integrity of grey and white brain matter.

Psychosocial factors such as enhanced mood, decreased weariness, and better sleep quality may also contribute to the cognitive benefits of cardiorespiratory fitness.

The researchers acknowledged numerous limitations, notably the study's observational character, which prevents clear cause-and-effect conclusions. Furthermore, the subjects were highly sedentary, which restricted the range of fitness levels seen. We did not test certain cognitive domains, such as language, leaving room for future research to explore these topics.

"These findings emphasize cardiorespiratory fitness as a critical health determinant for maintaining multidomain cognitive performance in older adults."  "Understanding the mediators of this association may assist in the creation of personalized exercise prescriptions that target [cardiorespiriratory fitness] to maximize cognitive health in the elderly."  The writers concluded.

Given the ageing global population and the increased frequency of cognitive decline and dementia, this study underscores the importance of regular aerobic exercise in maintaining cognitive health. The findings could help adapt fitness regimens for older persons to support their neurocognitive well-being.