2005 IRISH SCIENTIST YEAR BOOK

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Trinity College Dublin
�ine Kelly
A healthy mind in a healthy body

The Romans had a proverb, 'mens sana in corpore sano,' meaning 'a healthy mind in a healthy body'. Research worldwide, including in the Department of Physiology, TCD, shows that the Romans were really on to something. While we have known for a long time that exercise can protect general health and wellbeing, it now seems that exercise may help to preserve brain health also. For example, fitness levels have been associated with maintenance of brain function in age while physical activity has been linked with a reduced risk of development of Alzheimer's disease and dementia.

So, how can exercise act to improve brain health? The answer may lie with a group of proteins called growth factors. This family of proteins includes insulin-like growth factor (IGF) and brain-derived neurotrophic factor (BDNF). Many studies have demonstrated that exercise can increase BDNF concentration in the hippocampus, a brain region vital to learning and memory. Our studies have shown that rats undergoing a short period of exercise training perform better in learning and memory tasks than rats who are not exercise-trained, and that these improvements are linked to increases in hippocampal BDNF (see figure). Other laboratories have shown that, in rats, exercise can reduce the effects of brain damage and that, again, the key factor may be an increase in BDNF. The role of IGF appears to be equally important in mediating the protective effects of exercise; one specific role may be in modulating the structure of blood vessels in the brain.


Exercise significantly increases memory and hippocampal BDNF

It is obviously important to investigate whether the protective effects of exercise on the human brain result from the same mechanisms described in the rat brain. In an effort to tackle this question, we carried out a project analysing the effects of exercise on brain function and blood levels of growth factors in a group of young male students. We found that exercise training resulted in small but measurable improvements in learning and memory and that this was associated with increased levels of IGF in the blood, mirroring effects observed in the rat.

As scientific and medical breakthroughs extend life expectancy, the quality of life of the aged in terms of physical and mental well-being is of vital importance. Exercise is emerging as a possible means to maintain or improve brain health throughout life. Our challenge over the next number of years is to extend our work to further investigate the role of exercise as a cognitive enhancer and neuroprotectant in the aged brain and to discover the precise mechanisms by which it may trigger these remarkable effects.

Contact: Dr �ine Kelly, Department of Physiology,
Trinity College, Dublin 2;
E-mail: [email protected]