Mood disorders including depression are at the most present psychiatric disorders in present society. It is described that 16% population is estimated to be affected by major depression1 once during their life time. All symptoms of these mood disorders are collectively called ‘depressive syndrome’ and they are characterized by anxiety, feelings of guilt, long-lasting depressed mood and recurrent thoughts of death and suicide. Here we briefly point the benefits of the physical exercise – an accessible and healthy behavior that interferes in the neurobiology and deeply impact brain function.
One of the major needs in the field of depression research is a better understanding of the neural circuits in the brain that control mood under normal circumstances and mediate abnormalities in mood that are seen in depression. Given the pervasive symptoms of depression, it is likely that the pathophysiology of this disorder, and the mechanisms by which currently available treatments reverse its symptoms, involve numerous brain regions. Several works has begun to incorporate studies of amygdala, striatal, and hypothalamic circuits with studies of hippocampus and neocortex to formulate a more complete neural circuitry of mood and depression. The neocortex, in particular, is likely critical for features of depression which would appear to be peculiarly human (feelings of worthlessness, hopelessness, guilt, suicidality, etc.). Erickson et al. (2013) described that greater amount of physical activity is linked to less cortical atrophy, better brain function, and enhanced cognitive function. They observed that prefrontal and hippocampal areas are more benefited by exercise though the effects on the brain are relatively widespread. The specificity of these effects suggests a biological basis for the mechanisms by which physical activity influence cognition and neuropsychiatric dis7orders such as depression. The authors conclude that physical activity is an easy, accessible and promising intervention that can influence the brain enhancing cognitive and emotional function.
Exercise also leads to elevated levels of 5-HT in the brain and because of this, it is no surprise that there is increasing support for the value of exercise in reducing depressive symptoms. Physical exercise can be efficient in reducing depression and depressive symptoms. The antidepressant effect of exercise can be partly based on the 5-HT deficiency theory of depression. This theory is supported by the fact that most agents currently used as effective antidepressants enhance monoamine transmitter function and increases the efficiency of serotonergic transmission. Therefore, exercise can be exerting its widely recognized antidepressant effects through an increase in 5-HT levels in the brain. Other potential mechanisms are already being researched and the beneficial effects may take place through the modulation of BDNF. Ivy and colleagues have shown that serotonergic blockade inhibits BDNF mRNA activation following both exercise and antidepressant treatment. BDNF and 5-HT co-regulate each other and this interaction is undoubtedly important in depressive disorders. So, by inducing BDNF and other molecules as serotonin, exercise strengthens neuronal structure and facilitates synaptic transmission, improving brain functions that can reflect clinical improvement affecting the whole health.