Training promotes the formation of neurons

The aim of the study was to examine how a three‑month training program affects cognitive functions, mood, and biological indicators of new neuron formation in the hippocampus — the most important brain region responsible for memory and learning. The researchers relied on data from animal experiments, where physical activity improved cognitive performance and stimulated the emergence of new neurons from stem cells in the hippocampus. Now it was necessary to determine whether this mechanism works in humans.

The participants were randomly divided into two groups. 27 people performed combined workouts three times a week, which included aerobic exercise and strength training. The remaining 25 people were assigned to the control group and did not change their usual level of activity. Cognitive abilities were considered the main indicator of effectiveness — they were assessed using a special task involving the discrimination of similar objects (Mnemonic Similarity Task). This task directly depends on the functioning of the hippocampus and is sensitive to age‑related changes, as well as to early signs of Alzheimer’s disease.

After three months, the scientists did not find any significant improvements in cognitive tests. The effect of the training was still noticeable, as the participants in the training group showed a significant improvement in mood‑related indicators, even though they initially did not have pronounced depressive symptoms. The researchers conclude from this that even healthy people can benefit from regular training, which can noticeably improve their emotional state.

Another important result concerned the formation of new neurons. Direct measurement of this process in the human brain would be too invasive and ethically unacceptable for a clinical study. Therefore, experts used an indirect but reliable method: they took blood serum samples from the participants and added them to cultures of human hippocampal stem cells in the laboratory. This made it possible to understand which factors in the blood are capable of influencing the transformation of stem cells into neurons.

It turned out that the blood serum of people who had undergone a training program reduced the number of stem cells in a state of active division. At first glance, this sounds paradoxical: if fewer cells are dividing, does that mean neurogenesis has weakened? Professor Sandrine Thuret explains it differently: since the supply of stem cells in the brain is limited, the body can conserve some of them for future use instead of expending them all at once. It is likely that exercise helps the brain manage this reserve more rationally.

According to Sahand Farmand, one of the authors of the study, three months of regular exercise proved to be enough to noticeably improve mood even in healthy people. However, cognitive benefits, especially those related to the functioning of the hippocampus, may manifest later, either with longer sessions or with more intense loads.

Interestingly, for some participants, the effect of the training was particularly pronounced: their mood, laboratory indicators, and even cognitive results improved noticeably.

The study is part of a larger project being conducted jointly with APC Microbiome Ireland at University College Cork. It additionally examines how exercise affects the gut microbiota and the “gut—brain” axis.

Thus, even without an immediate effect on memory and thinking, regular physical activity gives the brain and psyche important benefits: it improves mood and probably helps to preserve and intelligently use the cellular reserve of the hippocampus, all this can be a significant prevention of age-related changes.