It has long been speculated that there is a relationship between exercise and it’s effects on mental health. However, it has not been until recent years that evidence has shown that exercise indeed has a profound benefit on brain function. Studies show that humans and animals that are engaged in regular physical activity have an improvement in learning and memory, protection of overall mental health, and also suggest that an active and healthy lifestyle may help in reversing the effects and causes of depression. One of the most intreresting changes caused by exercise is Neurogenesis, or the creation of new neurons. New neurons are created in the hippocampus, however the exact process behind this neurogenesis is still unknown. It is possible that stresses caused by exercise result in a spike in calcium in neural cell, which, in turn, causes hippocampal neurons to run through a cell building process. This cell building process activates the BDNF (Brain-Derived Neurotrophic Factor) gene, which creates BDNF proteins that aid the process of neurogenesis. Thus it is shown that BDNF is generated as a protective response to stress, as it acts not only to generate new neurons, but also to protect existing neurons. (Cotman, Berchtold & Christie, 2007) However, BDNFs do more than protect, they also repair. For example, in a comparison between sedentary and active mice, scientists found that mice which were generally more active rebuilt damaged brain tissue more efficiently than sedentary mice. This effect was not observed when the active mice were injected with a blocking agent used to discourage the growth of cells, thereby eliminating a possible variable and showing that exercise actively stimulates injured neurons to regenerate and repair themselves. (Mattson, Wenzhen, Ruqian & Zhihong, 2004) In both human and animal studies, exercise has been shown to improve performance in cognitive tasks such as encoding and retrieval. Studies of rodents in mazes found that, when compared to sedentary animals, exercised animals showed improved performance in solving the mazes and displayed enhanced memory for the location of provided escape platforms. Likewise, human studies have shown that cognitive performance is improved due to physiological arousal, which speeds mental processes and enhances storage and retrieval of memories. Ongoing exercise interventions have provided favorable results in older adults and children. (Van Praag, 2009)
While exercise is very beneficial to the health and structure of brain cells, it also has been shown to have positive effects on many psychological conditions and mood disorders. According to a study by C. Taylor, J. Sallis, and R. Needle (1985), depression affects about 5 to 10 percent of the american population. Depressive illness is strongly associated with physical disease, and research has reported that depressed patients often demonstrate reduced physical health status. Thus, the rationale for exercise as an intervention may extend beyond the potential benefits for depression since exercise can also provide a range of physiological health benefits that traditional interventions do not. The most well known explanation for the mood altering effects of exercise is the endorphin hypothesis, which proposes that exercise is associated with the release of endogenous opiates such as endorphins resulting in improved mood and feelings of well-being. Similarly, the monoamine hypothesis has suggested that exercise results in an increase in brain neurotransmitters (dopamine, serotonin and noradrenaline) that typically are found to be reduced with depression. While studies involving animals have indicated that exercise increases levels of serotonin and norepinephrine in the brain, this relationship remains unclear in humans. (Daley, 2008)
As more research is done on the subject of exercise and it’s effects on mental health, more is learned about the delicate balance between the body and the mind. The information does not stop here but also sheds light on possible techniques to treat alzheimers patients and aid in the addiction recovery process. It is clear from the information given in these, and many more, articles that a person can live a much happier and healthier life by choosing to devote a small portion of their day to exercise. As researchers learn more about the relationship between physical and mental health hopefully it will help us to understand more about the mind so that we may deliver relief to those who suffer from mental illness.

Works Cited
Cotman, C. W., Berchtold, N. C., & Christie, L. (2007). Exercise builds brain health: key roles of growth factor cascades and inflammation. TRENDS in Neurosciences, 30(9), 464-472.

Daley, A. (2008). Exercise and depression: A review of reviews. J Clin Psychol Med Settings, (15), 140-147. doi: 10.1007/s10880-008-9105-z
Taylor, C. B., Sallis, J. F., & Needle, R. (1985). The relation of physical activityand exercise to mental health. Public Health Reports, 100(2), 195-202.
Mattson, M. P., Wenzhen, D., Ruqian, W., & Zhihong, G. (2004). Prophylactic activation of neuroprotective stress response pathways by dietary and behavioral manipulations. NeuroRX, 1(1), 111-116.

Van Pragg, H. (2009). Exercise and the brain: something to chew on. Cell Press, 32(5), 283-290.