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Exercise training increases size of hippocampus and improves memory
Erickson KI, Voss MW, Prakash RS, Basak C, Szabo A, Chaddock L, Kim JS, Heo S et al.. Proceedings of the National Academy of Sciences of the United States of America, 2011-01-31
Topic: Brain proteins, microglia and lab models
The hippocampus shrinks in late adulthood, leading to impaired memory and increased risk for dementia. Hippocampal and medial temporal lobe volumes are larger in higher-fit adults, and physical activity training increases hippocampal perfusion, but the extent to which aerobic exercise training can modify hippocampal volume in late adulthood remains unknown. Here we show, in a randomized controlled trial with 120 older adults, that aerobic exercise training increases the size of the anterior hippocampus, leading to improvements in spatial memory. Exercise training increased hippocampal volume by 2%, effectively reversing age-related loss in volume by 1 to 2 y. We also demonstrate that increased hippocampal volume is associated with greater serum levels of BDNF, a mediator of neurogenesis in the dentate gyrus. Hippocampal volume declined in the control group, but higher preintervention fitness partially attenuated the decline, suggesting that fitness protects against volume loss. Caudate nucleus and thalamus volumes were unaffected by the intervention. These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.
Key findings
- The hippocampus shrinks in late adulthood, leading to impaired memory and increased risk for dementia.
- We also demonstrate that increased hippocampal volume is associated with greater serum levels of BDNF, a mediator of neurogenesis in the dentate gyrus.
- Hippocampal volume declined in the control group, but higher preintervention fitness partially attenuated the decline, suggesting that fitness protects against volume loss.
- These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.
Why it matters
In a randomised trial of 120 older adults, aerobic exercise training grew the front part of the hippocampus, a memory region that normally shrinks with age, by about 2% and improved spatial memory; in the control group hippocampal volume declined, and two other brain regions were unchanged. Larger gains went with higher blood levels of BDNF, a growth factor. The trial measured brain size and memory in ageing, not dementia or Alzheimer's disease.
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Study details
- Study designrandomized controlled trial
- Evidence strengthHigh
Limitations
This trial was in healthy older adults, not people with Alzheimer's disease or MCI, so it shows exercise can grow the hippocampus and improve memory in normal aging, not that it can reverse hippocampal loss once Alzheimer's pathology is present.
How this study scored 77/100
Published in a peer-reviewed journal, and it is a randomised controlled trial. Scored zero for sample size and effect reported because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Proceedings of the National Academy of Sciences of the United States of America) |
| Journal's citation record | 4 / 4 | Proceedings of the National Academy of Sciences: journal h-index 1,167 (OpenAlex, 2026-10-29) |
| Study design | 11 / 12 | A randomised controlled trial |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2011 — within 20 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (pubmed indexes it as a clinical or observational study) |
| Randomised / blinded | 1 / 2 | Randomised (as stated in the record) |
| Times cited | 7 / 7 | Cited 4,838 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 284.6 citations a year over 17 year(s) since 2011 |
| Impact for its field and year | 6 / 6 | Cited 64.9× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 4 / 6 | Cited by 67 other studies in this library |
| Still being cited | 4 / 4 | Cited 1,038 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Arthur F. Kramer: h-index 130 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | University of Pittsburgh: institution h-index 1,470 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 4 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 21282661) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 77 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock, L., et al. (2011). Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences of the United States of America. https://doi.org/10.1073/pnas.1015950108
Vancouver
Erickson KI, Voss MW, Prakash RS, Basak C, Szabo A, Chaddock L, et al. Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences of the United States of America. 2011. doi:10.1073/pnas.1015950108. PMID: 21282661.
BibTeX
@article{erickson2011-21282661,
author = {Erickson, K. I. and Voss, M. W. and Prakash, R. S. and Basak, C. and Szabo, A. and Chaddock, L. and Kim, J. S. and Heo, S. and others},
title = {{Exercise training increases size of hippocampus and improves memory}},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {2011},
doi = {10.1073/pnas.1015950108},
pmid = {21282661},
url = {https://doi.org/10.1073/pnas.1015950108}
}
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