Experimental Analysis on the Effects of Physical Activity on Young Adults with Depression
Stella Vila
Oakland University
Experimental Analysis on the Effects of Physical Activity on Young Adults with Depression
With 14.8 million American adults affected and a staggering $52 billion deficit due to lost workplace productivity, major depressive disorder has become one of the largest, and fastest growing, economic issues in United States (University of Michigan Depression Center, 2016). Along with increased economic burden, individuals with clinical depression also increase their susceptibility to developing other medical conditions; for example, those diagnosed with clinical depression are four times as likely to suffer from a myocardial infarction, more commonly known as a heart attack, than individuals without a history of the illness (Depression and Bipolar Support Alliance, 2016). Studies show that due to stimulating the release of endorphins, otherwise known as feel-good hormones, exercise is one of the most effective and recommended methods in combatting depression (Craft & Perna, 2006). In fact, as seen in Searle et al.’s study, a large majority of general practitioners heavily recommend physical activity, alongside prescribed antidepressants, to their clinically depressed patients (2012). Despite these studies, only 40% of college students, age 18-24, regularly engage in physical activity three or more times a week (New York University). Considering the widespread prevalence, increased susceptibility to other ailments, and financial burden major depressive disorder poses, it is significant to better understand how fitness affects individuals diagnosed with the mental illness, as this may have numerous benefits.
Gudmundsson, et al. (2015) examined middle-aged women’s self-reported physical activity and depressive symptoms for a span of 32 years, between 1974 and 2005. Participants who reported decreasing physical activity over time evidenced higher depression scores throughout the study. The longitudinal study concluded that higher depression scores were related to declining levels of physical activity.
Mata, Thompson, Jaeggi, Buschkuehl, & Jonides (2012) studied depression and physical activity among college-aged students. Contrasting to the study conducted by Gudmundsson, et al. (2015), this study only lasted seven days and examined 53 clinically depressed individuals, as well as 53 controls who had never been diagnosed with a mental illness. Eight times per day for the entirety of the week, the two groups were asked to report their physical activity and affect (positive or negative). Throughout the entirety of the study, participants with depression reported lower positive affect and higher average negative affects when compared to the control group. Both groups, though, reported higher levels of positive affect after physical activity. The study also noted that longer duration and higher intensity of physical activity increased positive affect significantly in comparison to short duration, lower intensity physical activity. The study concluded that regardless of mental health, physical activity was related to higher positive affect, especially when the activity was self-initiated (otherwise known as leisure-time physical activity).
McKercher, et al. (2009) examined adults, aged 18-40, and their self-reports of depression and physical activity. Much like research done by Mata, et al. (2012), McKercher, et al.’s research focused on the various domains of physical activity (long duration versus short duration, for example). The study concluded that individuals that partook in moderate-intensity and moderate-duration physical activity reported nearly 50% lower prevalence of depressive symptoms than those that were sedentary; yet, individuals that reported partaking in high-intensity and long-duration physical activity reported nearly double prevalence of depressive symptoms than sedentary individuals.
Pickett, Yardley, & Kendrick (2012) examined leisure-time physical activity (self-initiated activity) and its effect on depressive symptoms, versus non-leisure time physical activity (work-related activity) and its effect on depression within adults. The researchers asked their participants to report their physical activity (duration, intensity, and type) and affect (positive or negative). Much like Mata, et al.’s study (2012), it was concluded that leisure-time physical activity was related to the alleviation of depressive symptoms, as it increased the participants’ positive affect and reduced their negative affect. Non-leisure time physical activity did not have any notable effect on depression.
Mouissi (2015) examined adolescents’ self-reports of physical activity, as well as depressive symptoms. Like all previously discussed research, this study indicated an inverse relationship among physical activity and depression; as physical activity increased, reports of depressive symptoms decreased, and as physical activity decreased, reports of depressive symptoms increased.
The present study examines the relationship between physical activity and self-reported depression levels in Oakland University students using observational analysis. In support of previous literature, we hypothesize that if participants partake in leisure-time physical activity, then they will report lower levels of depression because physical activity causes positive changes in participants’ affect.
Methods
Participants
One-hundred fifty students from a large Midwestern university will be recruited through the psychology department subject pool. The advertisement on SONA stated that participants must be between the ages of 18-24, with no other specified criteria. All proposed methods will be approved by the university’s Institutional Review Board prior to participant recruitment.
Procedure
Potential participants will access information about the study using the psychology department subject pool website. Those interested will be directed to call the lab to determine eligibility. Participants will be excluded if they are younger than 18 or older than 24. Eligible participants will be given a set of instructions to follow the week prior to their first lab appointment. All participants will simply be told to partake in physical activity as they typically would. These directions will be administered to help eliminate participant bias and to exert a level of control over participants.
On their first lab appointment, participants will take a short questionnaire, which will ask about their gender, race, ethnicity, income, etc. Participants will then assess their own physical activity using the Saltin-Grimby Physical Activity Level Scale (SGPALS) (Grimby, et al., 2015). (Note: though the original survey asks for assessment of physical activity on a yearly basis, our research team has tweaked, as to measure an individual’s physical activity on a weekly basis). This survey assesses the duration and amount of physical activity, as well as the intensity. Participants will then, with the presence of a psychiatrist in the room, be given the Beck’s Depression Inventory (BDI) (Beck, et al., 1961) to determine their degree of depression. (Note: a psychiatrist must be present in order to ensure that questions are interpreted as intended, an ethical cautionary). Participants will then be required to come in on a weekly basis in order to complete these two surveys for the remainder of the semester.
Upon completion of the entire study, participants will be debriefed and then thanked for their participation with a $10 gift card and credit in the psychology course. When the study is completed, we will analyze the data to find any correlation. Considering the presence of nested data, we have chosen the multilevel model for our statistical analysis.
Materials
Saltin-Grimby Physical Activity Level Scale (SGPALS). The SGPALS scale (Grimby et al., 2015) will be used to assess participants’ level of physical activity for that specified week. The scale ranges from 1-4. With 1 meaning physically inactive (almost completely inactive, reading, watching television, watching movies, using computers or doing other sedentary activities, during leisure time), 2 meaning some light physical activity (physically active for at least 4 hours/week, such as riding a bicycle or walking to work, walking with the family, gardening, fishing, table tennis, bowling etc.), 3 meaning regular physical activity and training (spending time doing heavy gardening, running, swimming, playing tennis, badminton, calisthenics and similar activities, for at least 2-3 hours/week), 4 meaning regular hard physical training for competitive sports (spending time running, orienteering, skiing, swimming, playing football, handball, etc. several times per week).
Beck’s Depression Inventory (BDI). The Beck’s Depression Inventory (BDI) (Beck, et al., 1961) will be used to determine the participants’ degree of depression. The scale consists of 21-item, self-report rating inventory that measures characteristic attitudes and symptoms of depression. Each item has 4 responses to choose from, ranging from 0 to 3. An example item: I do not feel like a failure (0), I feel I have failed more than the average person (1), As I look back on my life, all I can see is a lot of failures (2), I feel I am a complete failure as a person (3). At the end of the survey, the score is totaled up: (1-10) these ups and downs are considered normal, (11-16) mild mood disturbance, (17-20) borderline clinical depression, (21-30) moderate depression, (31-40) severe depression, (40+) extreme depression. For ethical reasons, and in case there is confusion regarding an item, a psychiatrist will be present.
Discussion
This study was conducted to further support previous literature on the inverse relationship between physical activity and depression. These results can be used to draw casual conclusions about the relationship between physical activity and depression. However, this study is not without its limitations. A study conducted by McPhie & Rawana (2012) noted a relation between physical activity, depressive symptoms, and self-esteem among adolescents. In fact, when self-esteem was controlled, McPhie and Rawana noted that there was no longer much relation between physical activity and depression. The study concluded that self-esteem, though often-neglected in studies, poses relation to depressive symptoms. With that in mind, it is important to acknowledge that not including other variables, such as self-esteem, is a large weakness of this study. There are many possible variables that could potentially attribute to the change of an individual’s affect. Although the inverse relation exists among physical activity and depression, it is impossible to conclude any existing causation. Furthermore, this study only applies to college-aged students; the study does not allow our findings to be generalized to other populations, such as the elderly or adolescents. One of the most prevalent weaknesses in studies incorporating self-reports is the potential presence of a social desirability bias. This weakness, as expected, exists in this study. Participants may feel compelled to respond a certain way when completing the surveys, for various reasons. For example, a sedentary individual may feel embarrassed or ashamed of their inactive lifestyle; instead of recording a 1 on their SGPALS analysis, they may lie and report a more active lifestyle.
Though limitations exist within this study, there are plenty of strengths, as well. A major strength of this research was the questionnaire given to all of the participants at the beginning of the study. With those completed questionnaires, we are able to take into account demographic variances that could potentially distort data before drawing any conclusions. An additional strength is the fact that this is a longitudinal study, rather than a cross-sectional study. Rather than meeting with participants once and drawing conclusions, we are able to meet with participants once a week for four months and establish a much more certain cause-and-effect relationship regarding physical activity and depression.
As all good research does, our study has posed many implications. As previously stated, a study conducted by McPhie & Rawana (2012) concluded that self-esteem, though often-neglected in studies, poses relation to depressive symptoms. It is essential not to neglect this variable since managing self-esteem may be more beneficial than simply partaking in physical activity, in regards to alleviating depressive symptoms. Since our research did not even take into account the effect of self-esteem on depressive symptoms, it is a significant route of research to note. Further research could look at physical activity and self-esteem, both separately and together, and its effect on depression. Additionally, examining adults, elders, and adolescents is another great implication, since our study cannot generalize our findings to these specific populations (Pickett, et al., 2012).
In conclusion, this study, along with previous literature, is essential. If our claimed hypothesis is supported, it would be in individuals’ best interests to begin implementing a more active lifestyle in order to avoid economic burden and health hazards. Moreover, medical professionals could begin stressing even more-so the importance of exercise, not only for a healthy body, but a sound mind.
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