DEPRESSION

Associations of Vigorous Physical Activity with Depression: An Examination of NHANES Data 2007-2008



CHAPTER I

INTRODUCTION

1a. Current State of Depression

The International Classification of Disease (ICD) classifies depressive disorders into four categories: - not depressed, mild depression; moderate depression and severe depression. Each degree of depression has a set number of symptoms amongst ten decisive key symptoms. The ten key symptoms are: persistent sadness; loss of interest; and fatigue for most days for a time of two weeks; Next, self-blame or guilt, slowing of movements or agitation, suicidal acts or thoughts, increased or poor appetite, low self-confidence, indecisiveness or poor concentration, and disturbed sleep (ICD-10 depression diagnostic criteria, 2013). The symptoms are summed up and the resultant number is tied to a classified degree.

In 2000, depression was the 4th leading contributor of the global burden of disease measured by Disability Adjusted Life Years (DALYs). Depression is projected to become second overall in ranking for DALYs of all ages and both sexes and the second leading cause of DALYs in the age category 15-44 years (Mental Health and Mental Health Disorders, 2011). Depression affects people of all ages; however, most studies show that people between the age of 45 and 64 experience major depression most frequently (Mental Health and Mental Health Disorders, 2011). In terms of Years Lost due to Disability (YLD), the leading cause of disability measured is depression (Mental Health and Mental Health Disorders, 2011). Depression affects 121 million people in the world (Mental Health and Mental Health Disorders, 2011).

According to the CDC, 18.8 million American adults suffer from a depressive illness per year. Aforementioned, the problem of depression is considered the most prevalent mental health problem in the older generation defined as individuals from the age 45 years and upward (Workplace Health Promotion, 2011). Depression is an insidious problem in the workplace, costing employers in the United States $17 billion to $44 billion (Workplace Health Promotion, 2011). The insidious nature of depression is a major constraint in an employee's daily functioning which leads to an average of 4.8 missed work days, and 11.5 days of reduced productivity in a period of three months (Workplace Health Promotion, 2011). To combat the problem, Employers may offer costly mental health services such as visits to a therapist and medication (Workplace Health Promotion, 2011).

1b. Purpose of the Study

Physical activity improves the productivity of an individual suffering from depression (Lagerveld S.E. et al, 2010). A reduction in productivity is typically seen in employees in the workplace that suffer from depression (Workplace Health Promotion, 2011). Research by Lagerveld S.E. et al (2010) shows higher productivity levels from individuals suffering from depression when engaged in vigorous physical activity. This increase in productivity helps individuals suffering from depression in the work place by preventing job loss due to low work output (Lagerveld S.E. et al, 2010).

The current study is about the association between vigorous physical activity and depression. Physical activity is differentiated into usual physical activity, moderate physical activity and vigorous physical ...