How Walking Improves Memory and Cognitive Function

Your daily walk might be quietly growing the part of your brain that holds on to your life story.

Story Snapshot

Walking 3–4 times a week for 40 minutes can grow the memory center of the brain by about 1%
That same brain area usually shrinks 1–2% per year after age 50, so walking can help reverse the trend
The walking group in a key study not only changed their brains, they remembered better a year later
Dr. Alan Castel and Dr. Andrew Huberman say simple, regular movement beats “brain games” for lasting memory

Walking Turned Into A Memory Prescription

Psychologist Dr. Alan Castel and neuroscientist Dr. Andrew Huberman are not selling a brain app or miracle pill. They are pointing to something your grandparents already did: they walked. In their discussion, they highlight research in older adults who were randomly assigned to walk three to four times a week for about 40 minutes, or to do stretching that did not raise the heart rate much. Only the walking group showed a meaningful change in the brain’s memory center.

The key structure is the hippocampus, deep in the brain, which helps form and store facts, events, and places. After about age 50, the hippocampus typically shrinks 1–2% per year in volume. That shrinkage tracks with the “senior moments” many people fear. In the study Castel cites, the walking group actually increased hippocampal volume by about 1% over the year. Compared to slow decay, that is like turning a slow leak into a small refill.

What Changed In The Brain, And Why It Matters

Castel explains that the walking group did more than bulk up a brain scan. Their memory worked better a year later. That matters, because sometimes health headlines focus on pretty pictures of the brain but skip the real-world outcome. Here, both changed: structure and performance. Huberman repeats the dose in clear terms: brisk walking, 30–40 minutes, three to four times per week, as a form of regular cardiovascular exercise. This is not an extreme marathon plan; it is a repeatable habit for most adults.

Neuroscience gives a few clues about why movement helps. Other work Huberman has discussed shows that getting the heart rate up releases chemicals like brain-derived neurotrophic factor, which act like growth signals for brain cells. Exercise also improves sleep and mood, and those two alone protect thinking over time. Castel stays cautious about claiming one single pathway, but he firmly ranks physical exercise, especially walking, above most “brain training” tricks for real memory support.

Why Walking Beats Most “Brain Games” For Aging Well

Many older adults are told to download games that claim to sharpen the mind. Castel has spent years studying these tools and often calls them over-hyped. In his view, the best “brain training” is still free: move your body. In one favorite study he cites, the walkers did better in long-term memory tests than the stretching-only group, showing that plain movement beat a more passive routine even when both took the same amount of time. The key difference was sustained effort that raised the heart rate.

Castel and Huberman also talk about “superagers,” people who stay sharp into their 70s and beyond. These people tend to have a mix of habits: they stay socially engaged, keep a clear sense of purpose, and they move regularly. Walking fits that pattern perfectly. It can be done with friends, outdoors, without gear, and it rarely requires a doctor’s visit first. From a conservative, common-sense view, that beats depending on expensive programs or new drugs when a sidewalk and a pair of shoes are already in reach.

Turning The Science Into A Simple Weekly Plan

The takeaway from Castel’s work and the Huberman Lab discussion is strikingly practical. First, aim for walks that are long enough and frequent enough to count as real exercise: about 30–40 minutes, three or four times each week, at a pace where conversation is possible but your breathing is clearly deeper. Second, treat walking as a standing appointment, like church or a weekly family call. The benefits come from consistency over months, not from one heroic weekend hike.

Third, stack memory-friendly habits on top of your walks. Use the time to recall stories from your day, quiz yourself on names, or think through facts you want to keep. Castel teaches that “errorful retrieval” — trying to remember and sometimes failing — actually strengthens memory more than passive review. Walking raises alertness and blood flow. Adding active recall during the walk turns a simple exercise session into a powerful brain workout that respects both biology and personal responsibility.