Effect of aerobic exercise on hippocampal volume in humans: A systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of controlled trials
PubMed 29113943 · doi:10.1016/j.neuroimage.2017.11.007
What was done
A systematic review and random-effects meta-analysis of controlled trials evaluating the effect of aerobic exercise on human hippocampal volume across the lifespan. A systematic search identified 4,398 articles, of which 14 controlled trials comprising 737 participants were included in the primary analysis of total and unilateral (left/right) hippocampal volume changes.
What was found
Aerobic exercise showed no statistically significant effect on total hippocampal volume across the 737 participants. However, aerobic exercise had significant positive effects on left hippocampal volume compared with control conditions. Post-hoc analyses indicated these effects were driven by exercise preventing volumetric decreases that occur over time. The abstract reports no numerical effect sizes, confidence intervals, or p-values.
Why it matters
This meta-analysis clarifies equivocal findings in human studies, demonstrating that aerobic exercise supports brain health primarily through left hippocampal volumetric retention rather than total structural enlargement.
Limits
The abstract reports no numerical effect sizes, variance estimates, or p-values. The combined sample size is modest (737 participants across 14 studies). The abstract does not specify participant health status, age distribution, exercise parameters (dose, duration, intensity), or whether all included controlled trials were randomized.
Cited by
- context Interventional trials show that one year of aerobic exercise leads to enlargement of the hippocampus and improvements in memory function compared to stretching.