Exercise for brain health: a four-part plan for memory
Updated: 11 hours ago
The short answer
The hippocampus, the part of your brain that stores new memories, shrinks with age. In a randomized trial, a year of brisk walking grew its front part by 2 percent, while it shrank in a stretching and toning group. The plan built from the trials has four parts: walk briskly 3 days a week, building from 10 to 40 minutes; keep it hard enough that you can talk but not sing, and progress when it gets easy; strength-train 2 other days, legs first, heavy enough to get stronger; and take an easy 10-minute walk before anything you need to remember.
What we cover
Part 1, the walk. In 120 older adults, a year of walking 3 days a week, built up from 10 to 40 minutes, increased the size of the front of the hippocampus by 2 percent; it shrank in the stretching and toning group. More growth went with higher levels of BDNF, a protein linked to new brain cell growth, and fitter people lost less. Primary source
Part 2, how hard and how much. Across 36 trials in adults over 50, exercise improved memory and thinking; sessions of 45 to 60 minutes at moderate intensity or higher were linked with the benefit. Primary source
Part 3, strength. In 100 adults with mild cognitive impairment, 6 months of high-intensity strength training 2 to 3 days a week left 48 percent with normal scores on the main memory and thinking test, against 27 percent without strength training. Primary source Brain scans showed gray matter growth tied to the improvement and less progression of small vessel damage. Primary source Strength gains, especially leg strength, explained the benefit. Primary source
Part 4, the 10-minute move. In healthy young adults, 10 minutes of very light exercise improved the ability to tell similar memories apart. Primary source In 35 healthy older adults, 20 minutes of moderate to vigorous cycling temporarily worsened the same skill, so keep this one easy. Primary source
Before you start. People who are not exercising and have heart, metabolic or kidney disease, or who have symptoms such as chest pain, are advised to get medical clearance first. Source
Timestamps
0:00 Can exercise sharpen memory and grow the hippocampus?
0:53 Meet Dr. Sean Hashmi
1:50 Part one: brisk walking three days a week
2:49 Part two: intensity and progression
3:45 Part three: strength training
5:24 Part four: the easy ten-minute move
6:22 Before you start: who needs medical clearance
7:07 Your first week
References
Erickson KI, et al. Exercise training increases size of hippocampus and improves memory. Proc Natl Acad Sci U S A 2011;108(7):3017-22. https://doi.org/10.1073/pnas.1015950108 Randomized controlled trial.
One year of aerobic walking increased anterior hippocampal volume by about 2 percent in older adults. Evidence type: randomized trial.
Northey JM, et al. Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. Br J Sports Med 2018;52(3):154-160. https://doi.org/10.1136/bjsports-2016-096587 Systematic review and meta-analysis.
Exercise improved cognition in adults over 50 across the trials reviewed. Evidence type: systematic review and meta-analysis.
Fiatarone Singh MA, et al. The Study of Mental and Resistance Training (SMART) study. J Am Med Dir Assoc 2014;15(12):873-80. https://doi.org/10.1016/j.jamda.2014.09.010 Randomized, double-blind, double-sham controlled trial.
High-intensity strength training improved cognitive outcomes in adults with mild cognitive impairment. Evidence type: randomized trial.
Suo C, et al. Therapeutically relevant structural and functional mechanisms triggered by physical and cognitive exercise. Mol Psychiatry 2016;21(11):1633-1642. https://doi.org/10.1038/mp.2016.19 Imaging analysis of a randomized controlled trial.
Brain imaging linked exercise-related structural changes to cognitive improvement in the SMART trial. Evidence type: imaging analysis of a randomized trial.
Mavros Y, et al. Mediation of cognitive function improvements by strength gains after resistance training in older adults with mild cognitive impairment. J Am Geriatr Soc 2017;65(3):550-559. https://doi.org/10.1111/jgs.14542 Secondary analysis of a randomized controlled trial.
Greater strength gains explained part of the cognitive benefit of resistance training. Evidence type: secondary analysis of a randomized trial.
Suwabe K, et al. Rapid stimulation of human dentate gyrus function with acute mild exercise. Proc Natl Acad Sci U S A 2018;115(41):10487-10492. https://doi.org/10.1073/pnas.1805668115 Acute exercise study with functional MRI.
Ten minutes of very light exercise improved memory discrimination in healthy young adults. Evidence type: acute exercise study.
Callow DD, et al. Acute cycling exercise and hippocampal subfield function and microstructure in healthy older adults. Hippocampus 2023;33(10):1123-1138. https://doi.org/10.1002/hipo.23571 Within-subject crossover study.
A harder twenty-minute cycling bout temporarily worsened memory discrimination in healthy older adults. Evidence type: within-subject crossover study.
One study explained in plain language every week, with sources attached, plus the free metabolic health guide: https://guides.selfprinciple.org/metabolic
This content is for educational purposes only and is not medical advice. Always consult your healthcare provider for individual care. The views expressed are Dr. Hashmi's own and do not represent his employer.
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