Cardiorespiratory fitness may be used as a predictor of cognitive health, according to study findings published in the British Journal of Sports Medicine.

Researchers used data from the UK Biobank to explore the relationships between cardiorespiratory fitness and cognitive function and dementia risk. Individuals without dementia who were aged between 39 and 70 were included in the study and followed for 12 years.

Using a 6-minute submaximal exercise test on a stationary bike, cardiorespiratory fitness score was estimated and tertiled as low, moderate, and high. At baseline, global cognitive function was assessed using a battery of neuropsychologic tests. Using the polygenic risk score for Alzheimer disease (AD), genetic predisposition for dementia was estimated. Linear, Poisson, and Laplace regression were used in statistical analyses.

A total of 61,214 individuals (mean age, 56.33; women, 51.96%) were included in the study. The mean values of age- and sex-specific cardiorespiratory fitness for the low (n=20,408), moderate (n=20,405), and high (n=20,401) groups were -1.02, -0.10, and 1.12, respectively.

Higher cardiorespiratory fitness (per 1-SD increment) was dose-dependently associated with better global cognitive function (b, 0.03; 95% CI, 0.02-0.03), prospective memory (b, 0.03; 95% CI, 0.02-0.04), processing speed (b, 0.03; 95% CI, 0.02-0.04), and verbal and numeric memory (b, 0.05; 95% CI, 0.05-0.06).

Over the course of follow-up (mean, 11.72 years), a total of 553 participants developed dementia. Higher cardiorespiratory fitness (per 1-SD increment) was dose-dependently associated with reduced risks for all dementia (incidence rate ratio [IRR], 0.81; 95% CI, 0.73-0.89) and AD (IRR, 0.83; 95% CI, 0.72-0.97). Stratified by cardiorespiratory fitness tertile, rates of all dementia (IRR, 0.60; 95% CI, 0.48-0.76) and AD (IRR, 0.62; 95% CI, 0.43-0.89) were lower among those with high vs low cardiorespiratory fitness.

In participants with high vs low cardiorespiratory fitness, the onsets of all dementia and AD were delayed by 1.48 years (95% CI, 0.54-3.01) and 1.77 years (95% CI, 0.54-3.01), respectively.

Among those with moderate and high polygenic risk scores, high vs low cardiorespiratory fitness attenuated the risk for all dementia by 35% (IRR, 0.65; 95% CI, 0.52-0.83).

Study limitations include the reduced generalizability of results to more diverse sample populations, potential underestimation of dementia incidence, and possible residual bias.

“Future research on the relationship between CRF [cardiorespiratory fitness] and brain health, especially in older adults, is warranted, and the mechanisms by which CRF modifies the relationship between genetic risk and dementia deserve further investigation,” the study authors concluded.