Exercise and the brain: Evidence-Based Supplement Guide

The hippocampus is a brain region involved in memory, and it shrinks in late adulthood (PMID 21282661). In a randomised trial in 120 older adults, aerobic exercise training increased the size of the front part of the hippocampus by 2 percent, and spatial memory improved (PMID 21282661). The authors estimate that this offset one to two years of age-related loss (PMID 21282661). In the comparison group, hippocampal volume declined, and people who were fitter at the start lost less (PMID 21282661). Exercise also raises BDNF, a growth factor that supports nerve cells, in the blood. A meta-analysis of 29 studies found a moderate rise in BDNF after one session, a larger response once exercise was regular, and a small rise in resting levels (PMID 25455510). In the hippocampus trial, the gain in volume went with higher blood BDNF (PMID 21282661).

1. **Make aerobic exercise a regular habit.** Aerobic training enlarged the hippocampus in older adults in the trial (PMID 21282661). 2. **Keep it going over time.** Regular exercise strengthened the BDNF response to each session (PMID 25455510). 3. **Build and keep aerobic fitness.** In the comparison group, people who were fitter at the start lost less hippocampal volume (PMID 21282661).

A single session raised BDNF, and a programme of regular exercise strengthened that response and raised resting levels a little (PMID 25455510). The hippocampus result came from a training programme compared with a control group, not from one session (PMID 21282661).

- **The hippocampus finding comes from one trial of 120 older adults** (PMID 21282661). - **The link between hippocampal growth and BDNF was an association** measured in blood (PMID 21282661). - **BDNF rose less in studies with more women** (PMID 25455510). - **This guide has not been reviewed by a clinician.** `reviewStatus` above says so.

- **If you have a long-term health condition or take regular medicines, check with a clinician before starting a new exercise programme.** - **If you notice changes in your memory, speak with a clinician** rather than relying on exercise alone.

No ingredient is linked from this guide. It covers what exercise does in the brain, and it does not point to a product.

| PMID | Title | | --- | --- | | 21282661 | "Exercise training increases size of hippocampus and improves memory" | | 25455510 | "A meta-analytic review of the effects of exercise on brain-derived neurotrophic factor" |