Greater Cardiorespiratory Fitness Linked to Increased Gray Matter Volume in the General Population

A higher level of cardiorespiratory fitness is associated with greater gray matter volume in the temporal, frontal, and cerebellar regions of the brain, a study in Mayo Clinic Proceedings suggests.¹

The study included 2103 adults (age range, 21-84 years; mean ± standard deviation [SD] age, 52.34 ± 13.10 years) from 2 independent population-based cohorts: the Study of Health in Pomerania (SHIP) and SHIP-Trend. Researchers assessed participants’ cardiorespiratory fitness by assessing peak oxygen uptake (VO₂peak), oxygen uptake at the anaerobic threshold (VO₂@AT), and maximal power output (W_max) from cardiopulmonary fitness testing on a bicycle ergometer.²

To evaluate the correlation between cardiorespiratory fitness and brain volume, researchers examined magnetic resonance imaging (MRI) brain data and computed these data into regression models adjusted for age, sex, education, smoking, body weight, systolic blood pressure, glycated hemoglobin level, and intracranial volume.

Although volumetric analyses showed consistent positive associations of cardiorespiratory fitness measures with total brain volume and gray matter volume, there was no association with total white matter volume. According to a multivariable adjusted analysis, a 1-SD increase in VO₂peak was associated with a 5.31-cm³ (95% CI, 3.27-7.35 cm³) increase in greater gray matter volume. In addition, the 1-SD changes in VO₂@AT and W_max were associated with 1.79-cm³ (95% CI, 0.22-3.36 cm³) and 5.70-cm³ (95% CI, 3.61-7.80 cm³) increases in gray matter volume, respectively.

In addition, there were strong associations between VO₂peak and gray matter volume of the left middle temporal gyrus (228 voxels; P_peak <.001), right hippocampal gyrus (146 voxels; P_peak =.004), left orbitofrontal cortex (348 voxels; P_peak <.001), and left and right cingulate cortices (68 and 43 voxels, respectively; P_peak =.01 and P_peak =.02, respectively).

Limitations of this study include the cross-sectional nature of the MRI assessments and the possibility of residual confounding due to the lack of adjustment for several different unmeasured confounding factors.

Researchers from this study also suggest that cardiorespiratory fitness may have a stronger influence in people ≥45 years of age. In an accompanying editorial, Mayo Clinic researchers wrote that “this is encouraging because hippocampal atrophy and a decline in recent memory are commonly observed features of aging” and that “[i]f some of these aging changes could be counteracted by lifestyle changes, this would send a positive message to older individuals.”²

References

1. Wittfeld K, Jochem C, Dörr M, et al. Cardiorespiratory fitness and gray matter volume in the temporal, frontal, and cerebellar regions in the general population. Mayo Clin Proc. 2020;95(1):44-56.
2. Petersen RC, Joyner MJ, Jack CR Jr. Cardiorespiratory fitness and brain volumes (editorial). Mayo Clin Proc. 2020;95(1):6-8.