Research in humans and animals has shown that exercise improves mood and cognition. Physical activity has been consistently shown to be associated with improved physical health, life satisfaction, cognitive functioning, and psychological well-being. Conversely, physical inactivity appears to be associated with the development of psychological disorders.
Physical activity also causes a robust increase in neurogenesis in the dentate gyrus of the hippocampus, an important brain area for learning and memory. The results of epidemiological studies (cross-sectional, prospective and retrospective) support a positive relationship between cognition and physical activities. They include supramolecular mechanisms (e.g. neurogenesis, synaptogenesis, and angiogenesis) which, are in turn controlled by molecular mechanisms, such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1), hormones and second messengers.
An active lifestyle might prevent or delay loss of cognitive function with aging or neurodegenerative disease. Exercise could involve common cellular pathways important for neurogenesis, cell survival, synaptic plasticity and vascular function. Optimal maintenance of brain health might depend on exercise. The beneficial effects of exercise are likely to be mediated in part by hippocampal neurogenesis. Further investigation into the functional significance of neurogenesis, by designing behavioral tasks that are specific for the dentate gyrus, will help to determine the relative contribution of the new cells.
Exercise inşuences brain vasculature. In particular, physical activity increases the proliferation of brain endothelial cells and angiogenesis throughout the brain. Growth factors such as insulin-like growth factor (IGF) and vascular endothelial growth factor (VEGF) play an important role in the angiogenic and neurogenic effects of exercise on the brain. The neurotrophin BDNF is considered to be the most important factor upregulated by physical activity because it has an important role in synaptic plasticity and cell genesis, growth and survival. Interestingly, there is a positive interaction between BDNF expression and serotonin. Serotonin receptor activation enhances BDNF expression in hippocampal cells, BDNF is recognized to be a key protein modulating brain plasticity and it is distributed widely throughout the brain. In humans, serum BDNF concentrations rise after exercise.
The involvement of such pathways, particularly in the hippocampus, may in turn lead to an improvement in cognitive function, enhancement of psychological well-being, and a decrease in the risks of Alzheimer's disease (AD) and dementia as well as decreases in symptoms of depression and anxiety. While intense exercise (as observed in conditions such as "excessive exercise" and "overtraining syndrome") leads to a lessening of anxiety, these mood variations are more related to the construct of depression than to the construct of anxiety.
Physiological effects of exercise and the benefits of exercise on psychiatric disorders will be discussed in the light of current literature in this presentation.
References:
1. Lista I, Sorrentino G. Biological mechanisms of physical activity in preventing cognitive decline. Cell Mol Neurobiol. 2010;30(4):493-503.
2. van Praag H. Exercise and the brain: something to chew on. Trends Neurosci 2009;32(5 ):283–90.
3. Little Exercise, Big Effects: Reversing Aging and Infection-Induced Memory Deficits, and Underlying Processes. Barrientos R. M., Frank M.G, Crysdale N.Y, Chapman T.R, Ahrendsen J.T at all. The Journal of Neuroscience, 2011; 31(32):11578 –86.
4. Christofoletti G, Oliani M.M, Bucken L.T, Gobbi S, Beinotti F, Stella F. Physical activity attenuates neuropsychiatric disturbances and caregiver burden in patients with dementia. Clinics (Sao Paulo). 2011; 66(4): 613–8.
5. Ma Q. Beneficial effects of moderate voluntary physical exercise and its biological mechanisms on brain health. Neurosci Bull. 2008;24(4):265-70.
6. van Praag H. Neurogenesis and exercise: past and future directions. Neuromolecular Med. 2008;10(2):128-40.
7. Ang. ET, Tai YK, Lo SQ, Seet R, Soong TW.Neurodegenerative Diseases: Exercising Toward Neurogenesis and Neuroregeneration. Front Aging Neurosci. 2010; 2: 25.
8. Tomporowski P. D., Lambourne K., Okumura M. S. Physical activity interventions and children's mental function: an introduction and overview. Prev Med. 2011; 52(Suppl 1): S3–S9.
9. Fadillioglu E., Kaya B., Uz E., Emre M.H., Ünal S. Effects of Moderate Exercise on Mild Depressive Mood, Antioxidants and Lipid Peroxidation. Bull Clin Psychopharmacol 2000; 10(4):194-200.