Does exercise improve memory? What the science says

Exercise is one of the best-supported things you can do for your brain. But the headlines oversell some of it. Here’s what the studies show, and how much you need.

By the Daily Recall team · Updated October 3, 2026 · 10 sources

If there’s one lifestyle habit brain researchers agree on, it’s exercise. It’s good for your heart, mood and sleep, and all three matter for memory. But some of the most-shared claims, like “walking grows your brain”, deserve a closer look.

The study everyone cites

In 2011, Kirk Erickson and colleagues randomly assigned 120 inactive older adults to a year of either brisk walking (40 minutes, 3 times a week) or stretching and toning. In the walking group, the hippocampus, a region central to forming memories, grew by about 2%, which the authors described as reversing 1 to 2 years of age-related loss. In the stretching group it shrank. Bigger gains went with higher levels of BDNF, a protein that helps neurons grow and survive, and with better spatial memory.

It’s an important study, but not the last word. Other researchers questioned whether the memory improvement was really caused by the exercise. Later reviews disagree: a 2018 meta-analysis of 14 trials found aerobic exercise helped mainly by slowing hippocampal shrinkage, while a 2024 analysis of 8 trials in healthy older adults, co-written by Erickson himself, found no significant effect on its size.

What exercise does for the brain

Harvard Health groups the effects into two kinds:

• Direct: lower insulin resistance and inflammation, more growth factors such as BDNF, and new blood vessels in the brain.
• Indirect: better mood and sleep, and lower stress and anxiety, all of which affect how well you think and remember. See sleep and memory and stress and memory.

BDNF is the best-studied link. In animals, exercise clearly raises it in the hippocampus. In people, a review of 29 studies found each exercise session gives a short-lived rise in BDNF in the blood.

One workout vs a habit

A single session: a meta-analysis of 79 studies found a small boost to thinking during exercise, right after it, and after a delay. It’s small, but it’s one reason a walk before a hard task can help.

Over months and years: the bigger payoff. A 2018 review of 39 studies in adults over 50 found that exercise improved thinking, and that sessions of 45 to 60 minutes at moderate or vigorous intensity worked best.

What kind of exercise is best?

Aerobic exercise (walking, cycling, swimming, dancing) has the most research, especially for the hippocampus. Resistance training matters too: in that same 2018 review, strength training improved executive function, memory and working memory. Tai chi and mixed programs also helped. The best exercise is one you’ll keep doing.

How much? Steps and dementia risk

The World Health Organization recommends 150 to 300 minutes of moderate activity a week (or 75 to 150 minutes of vigorous activity), plus strength training on 2 or more days.

If you count steps: a 2022 study in JAMA Neurology followed more than 78,000 UK adults for about 7 years. About 9,800 steps a day was linked to roughly half the risk of dementia, and benefits started at about 3,800 steps. Pace mattered too: people whose fastest 30 minutes averaged a brisk walk had lower risk still. It was an observational study, and people who are already developing dementia may move less years before diagnosis, so it shows an association rather than proof.

Myths about exercise and the brain

• “You need 10,000 steps.” Benefits in the 2022 study started well below that.
• “Only cardio counts.” Strength training improves thinking too.
• “Exercise prevents dementia.” Physical inactivity is one of 14 modifiable risk factors identified by the 2024 Lancet Commission, but no single habit guarantees prevention. See why am I so forgetful?

Try it: before and after

A fun experiment: do this quick visual memory test now, then again after a brisk 10-minute walk.

The daily Recall game uses the same idea with a new puzzle each day. One walk won’t transform your score, but it’s a nice way to notice how you feel on active days versus sedentary ones.

If you have a heart condition, haven’t exercised in a while, or have other health concerns, check with a doctor before starting a new routine.

Sources

1. Erickson et al. (2011), PNAS: exercise training increases size of hippocampus and improves memory
2. Coen et al. (2011), PNAS letter: critique of the Erickson study
3. Firth et al. (2018), NeuroImage: aerobic exercise and hippocampal volume, a meta-analysis
4. Balbim et al. (2024), GeroScience: aerobic exercise and hippocampal volume in healthy older adults
5. Liu & Nusslock (2018), Frontiers in Neuroscience: exercise-mediated neurogenesis and BDNF
6. Chang et al. (2012), Brain Research: effects of acute exercise on cognition, a meta-analysis
7. Northey et al. (2018), British Journal of Sports Medicine: exercise and cognition in adults over 50 (summary)
8. Harvard Health: regular exercise changes the brain to improve memory and thinking skills
9. WHO 2020 guidelines on physical activity and sedentary behaviour
10. Alzforum: daily steps and dementia risk (del Pozo Cruz et al. 2022, JAMA Neurology)

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