There's very good evidence that physical activity helps delay or prevent cognitive decline.

Cognitive decline is defined as difficulty reasoning, processing and remembering — and its end state is dementia.

Total brain volume — and the thickness of key brain structures — are linked to brain health and performance.

We say that because prior evidence has clearly linked greater physical activity to having a bigger hippocampus — a small region located deep in the brain.

The hippocampus plays a key role in memory functions — especially long-term memory — and in spatial navigation.

And as a key part of the limbic system, the hippocampus plays a central role in our emotional lives.

Now, the results of a California-based study suggest that modest daily movement can boost hippocampus volume, with positive implications for brain performance and health.

UCLA study affirms walking’s brain benefits
The new study comes from scientists at the University of California Los Angeles (UCLA).

The UCLA researchers recruited 29 older adults with memory challenges and tracked their movement for seven days, using a step tracker to determine each participant’s average number of daily steps.

The volunteers were then divided into two groups:

  • More than 4,000 steps per day.
  • Fewer than 4,000 steps per day.

Each participant then underwent neuro-physical tests and an MRI scan of their brain (Siddarth P et al. 2017).

The results showed that those who walked more than 4,000 steps daily had a thicker hippocampus and thicker surrounding regions, compared with those who walked fewer than 4,000 steps.

In addition, the higher-step-count group displayed better information processing and attention, while those who took fewer steps had thinner brain structures and weaker mental functioning.

According to lead author Prabha Siddarth, Ph.D., “Few studies have looked at how physical activity affects the thickness of brain structures. Brain thickness, a more sensitive measure than volume, can track subtle changes in the brain earlier than volume and can independently predict cognition, so this is an important question.”

Exercise also enhances younger brains
What if you haven’t yet reached the age of 60?

Similar research on younger subjects shows similar — though slightly less pronounced — brain benefits.

Much of the clinical research into the effects of exercise on brain function involved either children or seniors.

However, a literature review published two years ago that examined the 14 available clinical studies that involved healthy people aged 18 to 50 found strong links between physical activity and better brain performance, especially memory and executive functions (Cox EP et al. 2016).

Exercise even appears to boost adolescents’ brains. The authors of a 2017 literature review covering 11 clinical studies concluded that exercise benefits executive function, memory, concentration, logical sequencing or other measures of cognitive function, but memory was most consistently improved by exercise.

In addition, extra exercise was linked to better overall academic performance in the participating adolescents (Li JW et al. 2017).

Veggies, fish (and omega-3 fish fat) also bring brain benefits
It’s clear that brain health — and volume — benefits greatly from exercise, but they also get a boost from certain whole foods.

The key dietary players appear to be green vegetables — thanks in part to their abundant antioxidants and B vitamins — and seafood, thanks to its unique omega-3 fatty acids, which don’t occur in plant sources of omega-3s such as dark leafy greens, flaxseed, and walnuts.

To learn more about research on green veggies and brain health, see Greens vs. Brain Aging and Colorful Greens and Veggies Keep Minds Sharp.

And for our coverage of studies linking fish and supplemental omega-3s to bigger brain volumes and better brain performance, see these articles:

It makes sense that greens and fish would aid brain health, because they formed key parts of the diets of early humans: see Did Humans Evolve on Fishy Diets? and Omega-3 Brain Evolution Theory Gets a Boost.


  • Cox EP, ODwyer N, Cook R, Vetter M, Cheng HL, Rooney K, O’Connor H. “Relationship between physical activity and cognitive function in apparently healthy young to middle-aged adults: A systematic review.” J Sci Med Sport. 2016 Aug;19(8):616-28. doi: 10.1016/j.jsams.2015.09.003. Epub 2015 Oct 9. Review. PubMed PMID: 26552574.
  • Li JW, O'Connor H, O'Dwyer N, Orr R. “The effect of acute and chronic exercise on cognitive function and academic performance in adolescents: A systematic review.” J Sci Med Sport. 2017 Sep;20(9):841-848. doi: 10.1016/j.jsams.2016.11.025. Epub 2017 Jan 24. Review. PubMed PMID: 28185806.
  • Siddarth P, Rahi B, Emerson ND, Burggren AC, Miller KJ, Bookheimer S, Lavretsky H, Dobkin B, Small G, Merrill DA. Physical Activity and Hippocampal Sub-Region Structure in Older Adults with Memory Complaints. J Alzheimers Dis. 2018;61(3):1089-1096. doi: 10.3233/JAD-170586. PubMed PMID: 29254088.