As part of the natural ageing process, our brains lose a bit of volume over time—which can lead to subtle changes or impairments in certain aspects of our cognitive abilities. One brain region that’s particularly sensitive to ageing is the hippocampus. This seahorse-shaped structure (yes, that’s actually where the name hippocampus comes from!) plays a key role in memory, learning and even our mood. It’s also home to neural stem cells—the cells that give rise to new neurons (in a process known as neurogenesis)—making it essential for many of the cognitive tasks we rely on every day.
To better understand the importance of neural stem cells—and, of course, the hippocampus—let’s walk through a simple example. Imagine your friend has moved from one apartment to another.
The old apartment? Third floor, red door, smelled like coffee. The new one? Also on the third floor, but this time a blue door and a hint of lavender in the air. They’re quite similar—same floor, similar layout—but with a few small differences. Without the help of your hippocampus and the stem cells located there, these two places might blend in your memory. You’d find yourself thinking, “Was the coffee smell at the red door or the blue one?” Thankfully, your hippocampus steps in to keep those memories distinct. It allows you to clearly remember which apartment had the red door and the scent of coffee and which had the blue door and smelled like lavender.
But here's the catch: even those memory-separating superpowers of the hippocampus aren’t immune to the effects of ageing. Rodent studies have shown that when scientists selectively disrupt the stem cells within this region, the brain's ability to separate similar memories—like those two apartments—starts to break down. So, the big question is: What can we do to support these stem cells and keep our hippocampus sharp? This is where exercise comes into the picture.
How does exercise affect the brain and the hippocampus?
So far, research from scientists around the world has shown that exercise can have a powerful impact on the health and behaviour of neural stem cells—at least in rodents. For example, it appears to support the maintenance of the stem cell pool and boost their ability to survive, grow, and develop into new neurons. But what’s actually driving these effects? While the exact mechanisms are still being studied, several factors are believed to be involved, including the release of antioxidants, the secretion of anti-inflammatory molecules, and increased blood flow to the brain. Blood flow appears to play a key role, as it helps transport all the exercise-induced beneficial substances to the brain. Together, these factors create a more supportive environment for stem cells to thrive. (For a detailed discussion of this topic, check out our review: Cognition on the move: Examining the role of physical exercise and neurogenesis in counteracting cognitive aging).
But here are the big questions: Do these mechanisms work the same way in humans? And does exercise actually help us distinguish between similar patterns more accurately and efficiently? To explore this, we're currently running an exercise intervention study—NeuroFit intervention trial—designed to investigate how physical activity affects hippocampus-dependent cognition (like pattern separation), mood, and overall mental well-being. As part of the study, participants have been assigned to either a control group (no exercise) or an exercise group.