Exercise interventions preserve hippocampal volume: A meta‐analysis

Abstract

Hippocampal volume is a marker of brain health and is reduced with aging and neurological disease. Exercise may be effective at increasing and preserving hippocampal volume, potentially serving as a treatment for conditions associated with hippocampal atrophy (e.g., dementia). This meta‐analysis aimed to identify whether exercise training has a positive effect on hippocampal volume and how population characteristics and exercise parameters moderate this effect. Studies met the following criteria: (a) controlled trials; (b) interventions of physical exercise; (c) included at least one time‐point of hippocampal volume data before the intervention and one after; (d) assessed hippocampal volume using either manual or automated segmentation algorithms. Animal studies, voxel‐based morphometry analyses, and multi‐modal interventions (e.g., cognitive training or meditation) were excluded. The primary analysis in n = 23 interventions from 22 published studies revealed a significant positive effect of exercise on total hippocampal volume. The overall effect was significant in older samples (65 years of age or older) and in interventions that lasted over 24 weeks and had less than 150 min per week of exercise. These findings suggest that moderate amounts of exercise for interventions greater than 6 months have a positive effect on hippocampal volume including in older populations vulnerable to hippocampal atrophy.

Aerobic exercise, cardiorespiratory fitness, and the human hippocampus

“…When examining the characteristics of the samples and interventions, the overall effect was significant for adults 65 years and older, interventions 24 weeks or longer, and interventions providing up to 150 min of exercise per week (Wilckens et al, 2021). These findings suggest that the parameters of the intervention and sample characteristics may account for some of the heterogeneity in findings across the field.…”

“…However, one of these studies reported an exercise adherence rate of only 36% (Krogh et al, 2014), raising methodological and theoretical questions about the inclusion of studies with both poor and good (>80%) adherence rates. A recent meta-analysis of exercise interventions found a significant reduction in control groups' total hippocampal volume from pre-to post-intervention, but not left or right hippocampal volume, while an overall increase in the intervention group was not significant (Wilckens et al, 2021).…”

“…However, one of these studies reported an exercise adherence rate of only 36% (Krogh et al, 2014), raising methodological and theoretical questions about the inclusion of studies with both poor and good (>80%) adherence rates. A recent meta‐analysis of exercise interventions found a significant reduction in control groups' total hippocampal volume from pre‐ to post‐intervention, but not left or right hippocampal volume, while an overall increase in the intervention group was not significant (Wilckens et al, 2021). When examining the characteristics of the samples and interventions, the overall effect was significant for adults 65 years and older, interventions 24 weeks or longer, and interventions providing up to 150 min of exercise per week (Wilckens et al, 2021).…”

“…A recent meta‐analysis of exercise interventions found a significant reduction in control groups' total hippocampal volume from pre‐ to post‐intervention, but not left or right hippocampal volume, while an overall increase in the intervention group was not significant (Wilckens et al, 2021). When examining the characteristics of the samples and interventions, the overall effect was significant for adults 65 years and older, interventions 24 weeks or longer, and interventions providing up to 150 min of exercise per week (Wilckens et al, 2021). These findings suggest that the parameters of the intervention and sample characteristics may account for some of the heterogeneity in findings across the field.…”

The Effects of Combined Physical and Cognitive Training on Inhibitory Control: A Systematic Review and Meta-Analysis

“…Similarly, increased default mode network (DMN) activity is associated with poorer inhibitory control ( Congdon et al, 2010 ), thus physical training’s decrease of DMN may have an indirect benefit on inhibitory control mechanisms ( Boraxbekk, Salami, Wåhlin & Nyberg, 2016 ; Li et al, 2017 ). Additionally, physical training literature has demonstrated structural and functional physical training induced benefits for memory ( Wanner, Cheng & Steib, 2020 ; Wilckens et al, 2020 ) and higher-level executive functions such as inhibition control ( Verburgh, Königs, Scherder & Oosterlaan, 2014 ; Xue, Yang & Huang, 2019 ). For example, regular physical training is associated with increased grey matter volume in the prefrontal cortices ( Erickson, Leckie, & Weinstein, 2014 ; Den Ouden et al, 2018 ), which support a range of executive functions including inhibitory control ( Aron, Robbins & Poldrack, 2014 ; Bari & Robins, 2013 ; Bird & Burgess, 2008 ; Kim, Choi & Chung, 2016 ; Kim & Sung, 2017 ; Park & Kim, 2017 ; Swick, Ashley & Turken, 2011 .…”