The study also suggests that this happens because exercise restores a brain chemical which promotes the production and maturation of new stem cells.
The study, was carried out by Chih-Wei Wu, Ya-Ting Chang, Lung Yu, Hsiun-ing Chen, Chauying J. Jen, Shih-Ying Wu, Chen-Peng Lo, Yu-Min Kuo, all of the National Cheng Kung University Medical College in Taiwan. The study appears in the November issue of the Journal of Applied Physiology, published by The American Physiological Society.
The hippocampus plays an important role in memory and learning. There is evidence that when fewer new stem or progenitor cells are produced in the hippocampus, it can result in impairment of the learning and memory functions.
The researchers built on earlier studies that found that the production of stem cells in the area of the hippocampus known as the dentate gyrus drops off dramatically by the time mice are middle age and that exercise can slow that trend. In the current study, the researchers wanted to track these changes in mice over time, and find out why they happen.
Researcher found that exercise improved the production of neural stem cells by 200% compared to the middle-aged mice which did not exercise.
In addition, the survival of new nerve cells increased by 170% and growth by 190% compared to the sedentary middle-aged mice.
Exercise also significantly enhanced stem cell production and maturation in the young mice. In fact, exercise produced a stronger effect in younger mice compared to the older mice.