It may be possible to increase the neuron reserve of the hippocampus – and thus improve preconditions for learning – by promoting neurogenesis via sustained aerobic exercise such as running.

Aerobic exercise, such as running, has positive effects on brain structure and function, for example, the generation of neurons (neurogenesis) in the hippocampus, a brain structure important in learning. It has been unclear whether high-intensity interval training (HIT), 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. In addition, individual genetic variation in the overall response to physical exercise likely plays a part in the effects of exercise on adult neurogenesis but is less studied.

Researchers from the Department of Psychology and from the Department of Biology of Physical Activity at the University of Jyväskylä studied the effects of sustained running exercise, HIT and resistance training on adult hippocampal neurogenesis in adult male rats. In addition to the commonly used Sprague-Dawley rats, rat lines developed by collaborators at the University of Michigan were also used: Rats with a genetically high response to aerobic training (HRT) and those with a low response to aerobic training (LRT). The exercise training period was 6 to 8 weeks (running, HIT or resistance training) during which control animals of the same rat line/strain remained in sedentary conditions in the home cage.

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 2-3 times more new hippocampal neurons at the end of the experiment. Resistance training had no such effect. Also the effects of HIT were minor. To conclude, only sustained aerobic exercise improved hippocampal neurogenesis in adult animals.

The result is important because, according to previous research, the new hippocampal neurons produced as a result of neurogenesis are needed among other things for learning temporally and/or spatially complex tasks. It is possible that by promoting neurogenesis via sustained aerobic exercise, the neuron reserve of the hippocampus can be increased and thus also the preconditions for learning improved – also in humans.

About this neuroscience research

The research report has been accepted for publication in the Journal of Physiology, a respected journal both in the field of neurosciences as well as physiology.

Funding: Research on the connection between physical exercise and the preconditions for learning is continued in the AFIS consortium funded by the Academy of Finland.

Source: Miriam Nokia – Academy of Finland

Image Credit: The image is in the public domain

Original Research: Abstract for “Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained” by Miriam S. Nokia, Sanna Lensu, Juha P. Ahtiainen, Petra P. Johansson, Lauren G. Koch, Steven L. Britton, and Heikki Kainulainen in Journal of Physiology. Published online February 4 2016 doi:10.1113/JP271552

Abstract

Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained

Aerobic exercise, such as running, has positive effects on brain structure and function, for example, adult hippocampal neurogenesis (AHN) and learning. Whether high-intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training (RT) has similar effects on AHN is unclear. In addition, individual genetic variation in the overall response to physical exercise likely plays a part in the effects of exercise on AHN but is less studied. Recently, we developed polygenic rat models that gain differentially for running capacity in response to aerobic treadmill training. Here we subjected these Low Response Trainer (LRT) and High Response Trainer (HRT) adult male rats to various forms of physical exercise for 6 to 8 weeks and examined its effects on AHN. Compared to sedentary animals, the highest number of doublecortin-positive hippocampal cells was observed in HRT rats that ran voluntarily on a running wheel while HIT on the treadmill had a smaller, statistically non-significant effect on AHN. AHN was elevated in both LRT and HRT rats that endurance trained on a treadmill compared to those that performed RT by climbing a vertical ladder with weights, despite their significant gain in strength. Furthermore, RT had no effect on proliferation (Ki67), maturation (doublecortin) or survival (BrdU) of new adult-born hippocampal neurons in adult male Sprague-Dawley rats. Our results suggest physical exercise promotes AHN most if it is aerobic and sustained, and especially when accompanied by a heightened genetic predisposition for response to physical exercise.

“Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained” by Miriam S. Nokia, Sanna Lensu, Juha P. Ahtiainen, Petra P. Johansson, Lauren G. Koch, Steven L. Britton, and Heikki Kainulainen in Journal of Physiology. Published online February 4 2016 doi:10.1113/JP271552

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