"It's often said that depression results from a chemical imbalance, but that figure of speech doesn't capture how complex the disease is."

According to a research from the Harvard Health Publications, it says that "depression doesn't spring from simply having too much or too little of certain brain chemicals. Rather, there are many possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems. Ii is believed that several of these forces interact to bring on depression."

For instance, there are a lot of underlying factors that helps trigger a person's 'depression' mode especially when that person is in a vulnerable stage.

The first historical understanding of depression was that depression was a spiritual (or mental) illness rather than a physical one.

Both the Ancient Greeks and Romans were divided in their thinking about the causes of melancholia. Hippocrates thought that melancholia was caused by too much black bile in the spleen and what was previously known as melancholia, deep sadness or gloom. Melancholia is now known as clinical depression, major depression, or simply depression and commonly referred to as major depressive disorder by many health care professionals.

What to do when you are depressed?

There actually numerous ways to channel your depression but it certainly differs from one person to another.  Some approach may be effective to a certain person but it doesn't mean that it will be as effective to another person who also suffers from depression.

However, in a research by Lynette L. Craft, Ph.D. and Frank M. Perna, Ed.D., Ph.D. entitled 'The Benefits of Exercise for the Clinically Depressed' it states that "Exercise is a behavioral intervention that has shown great promise in alleviating symptoms of depression. The current review discusses the growing body of research examining the exercise-depression relationship that supports the efficacy of exercise as an adjunct treatment. Databases searched were Medline, PsycLit, PubMed, and SportsDiscus from the years 1996 through 2003. Terms used in the search were clinical depression, depression, exercise, and physical activity. Further, because primary care physicians deliver important mental health services to the majority of depressed patients, several specific recommendations are made regarding counseling these patients on the adoption and maintenance of exercise programs."

To add to that, depression affects roughly 9.5% of the U.S. adult population each year, and it is estimated that approximately 17% of the U.S. population will suffer from a major depressive episode at some point in their lifetime. Depression has been ranked as the leading cause of disability in the United States, with over $40 billion being spent each year on lost work productivity and medical treatment related to this illness. Recent research suggests that between the years of 1987 and 1997, the rate of outpatient treatment for depression in the United States tripled and that health care costs related to this disorder continue to rise.

However, involvement in structured exercise has shown promise in alleviating symptoms of clinical depression. Since the early 1900s, researchers have been interested in the association between exercise and depression. Early case studies concluded that, at least for some, moderate-intensity exercise should be beneficial for depression and result in a happier mood. Furthermore, a relationship between physical work capacity (PWC) and depression appeared to exist, but the directional nature of this relationship could not be addressed via case and cross-sectional studies. However, researchers have remained interested in the antidepressant effects of exercise and more recently have utilized experimental designs to study this association.

Physical activity also helps to reduce stress and anxiety that leads to depression.  People have different triggers when it comes to depression but something to channel those balled-up feelings will help it feel a bit better.

The physical benefits of exercise-improving physical condition and fighting disease have long been established, and physicians always encourage people to stay physically active. Exercise is also considered vital for maintaining mental fitness, and it can reduce stress. Studies show that it is very effective at reducing fatigue, improving alertness and concentration, and at enhancing overall cognitive function. This can be especially helpful when stress has depleted your energy or ability to concentrate.

When stress affects the brain with its many nerve connections, the rest of the body feels the impact as well. So it stands to reason that if your body feels better, so does your mind. Exercise and other physical activity produce endorphins-chemicals in the brain that act as natural painkillers-and also improve the ability to sleep, which in turn reduces stress. Meditation, acupuncture, massage therapy, even breathing deeply can cause your body to produce endorphins. Conventional wisdom also stresses that a workout of low to moderate intensity makes you feel energized and healthy.