The health issue of the aged people is globally a matter of concern. Everyone knows that exercise is good both for the body and mind, but we cannot force all the aged people work out. The study by Professor Hideaki Soya at the University of Tsukuba has shown that light exercises without stress rises the cognitive function of memory and recall in hippocampus, rather than intensive exercises with stress. More intense the exercise is, more effective the training of skeletal muscle becomes. However, it is interesting that the improvement of cognitive function in hippocampus requires only light exercises that can be done even by low physical strength. Under the circumstances, the relationship between light exercise and memorization function in hippocampus was unclear.

Professor Soya collaborated with Professor Randeep Rakwal and other scientists, and the team conducted research on the effect of exercises in various settings such as intensity and period. They looked at what kind of exercise is effective to improve the cognitive function of hippocampus, the area of controlling memory and learning along with investigating the mechanism of neural network.

This time the research uses rats with different intensities of exercises and looked at the effects of running training to neural development in hippocampus and all related genome expressions.

As a result, only the light exercises enhance the growth of new cells. Light exercises show more than 1.5 times of genome change compared to the intense exercises. Besides, 93% genome of changes after intense exercises are replace specifically to the genome expressions of light exercises. Moreover, among the genes changed under the research settings. The team selected the critical factors by looking up the genes expressions: instead of BDNF, IGF1, and VEGF (thought as significant factors), other factors contributed this time. The mechanism of light exercises contributing to the cognitive function in hippocampus and neural development is as follows: IGF2 and IRS1 enhance the synthesis of proteins, APOE enhances the transportation of cholesterol, and IL 1βand TNF enhances a light inflammation.

This finding evokes the significance of the new factor in hippocampus function related to exercises, and also in future, it could be applied to improving the cognitive ability of the aged animals and model animals of brain diseases by light exercises.

Hippocampal neuroanatomical changes induced by different intensities of exercise. Effects of mild exercise (ME) or intense exercise (IE) on hippocampal DG volume (A), the number of Ki-67+ cells (marker of neuronal progenitor proliferation) (B), BrdU positive cells (marker of cell survival) (C) and BrdU+/NeuN+ cells (marker of newly generate matured neurons) (D). Representative photograph of the dentate gyrus (DG) from each group single-stained for Ki-67 (brown), or double-stained for BrdU (red) and NeuN (green) (E).

Original Paper

Koshiro Inoue, Masahiro Okamoto, Junko Shibato, Min Chul Lee, Takashi Matsui, Randeep Rakwal and Hideaki Soya, PLoS One, Long-term mild, rather than intense, exercise enhances adult hippocampal neurogenesis and greatly changes the transcriptomic profile of the hippocampus DOI: 10.1371/journal.pone.0128720