Cardiorespiratory fitness and brain volumes in men and women in the FINGER study.

Background: high cardiorespiratory fitness (CRF) is associated with larger brain volumes but data on sex differences in the association of CRF with brain volumes are scarce. We investigated whether the association of CRF with total grey matter (GM) and white matter volumes as well as medial temporal lobe and striatum volumes is different between men and women at increased risk for Alzheimer's disease (AD).

Methods: we used baseline data from The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) in which the inclusion criteria were set to select individuals with cognitive performance at the mean level or slightly lower than expected for age according to Finnish population norms. Our sub-study included 39 randomly selected men and 29 women aged 61-75 years. CRF was assessed as peak oxygen consumption (VO2peak) measured in a maximal exercise test on cycle ergometer. Brain structural imaging was performed using a 1.5-T scanner.

Results: in men, VO2peak was associated with cortical GM volume (β = 0.56, P = 0.001) and total GM volume (β = 0.54, P = 0.001). In women, no associations were found between VO2peak and brain volumes. VO2peak accounted for 23% and 1% of total variance of cortical GM volume as well as 25% and 4% of total variance of total GM volume in men and women, respectively.

Conclusion: CRF is associated with cortical GM and total GM volumes in elderly men at increased risk for AD, but not in women.