Running is not only good for keeping fit and healthy, it can also potentially boost brainpower.
Scientists found aerobic exercise increases neuron reserves in the brain's hippocampus, an area responsible for learning.
The research team, from the University of Jyväskylä in Finland, studied rats undergoing sustained running, high intensity training (HIT) and resisitance training.
The study found that only sustained aerobic exercise increased the production of hippocampal neurons in adult rats - HIT and resistance training had littel to no effect.
Lead researcher, Professor Heikki Kanulainen said: "The results indicate that the highest number of new hippocampal neurons was observed in rats that ran long distances and that also had a genetic predisposition to benefit from aerobic exercise.
"Compared to sedentary animals, HRT rats that ran voluntarily on a running wheel had two to three times more new hippocampal neurons at the end of the experiment."
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The training period lasted six to eight weeks for the test rats while control animals of the same strain were kept in a sedentary condition.
The study published in the Journal of Psychology concluded: "Aerobic exercise, such as running, has positive effects on brain structure and function.
"For example, the generation of neurons in the hippocampus, a brain structure important in learning.
"It has been unclear whether high-intensity interval training, referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training has similar effects on hippocampal neurogenesis in adulthood."