Exercise as it relates to Disease/The Effect of Physical Activity on Mental Health in Older Adults
This Wikibooks article is an analysis of the journal article "Physical Activity Reduces the Risk of Subsequent Depression for Older Adults".
What is the background to this research?
Depression is one of the worlds leading health problems and can be a precursor to several other chronic illnesses or diseases. Depression has a very broad range of characteristics that aren't always that easy to recognize, some of these including; fatigue, irritability, trouble concentrating, insomnia or sleeping way too much, just to name a few.
The correlation between physical activity levels and depression has been studied a lot, but no real definite result has come from it. Past studies have had a mixture of results and no real result could be concluded as there were too many limitations to the studies.
This study looks at the comparison of higher levels of physical activity on depression without the exclusion of disabled subjects as previous studies had.
Where is the research from?
The subjects who particpated in this study were members of the Alameda County Study, which was a broad study which examined the relationship between lifestyle and health and has followed the same cohort of 6,928 adults since 1965 . Alameda County is located on the east side of San Francisco Bay and includes the cities of Oakland and Berkeley, California. At the time of the initial study the county was a good representative of the population of the United States in terms of age and ethnicity.
What kind of research was this?
The research conducted was a longitudinal study, as it followed the same group of individuals since 1965 and a follow up was conducted every 5 years after that, the most recent being 1999. 
Previous studies were conducted but took different approaches therefore the evidence concluded in the end is much different to what was concluded in this study, for example some studies showed that physical activity only influenced women rather than men because men were not to have depressive symptom  and some didn’t even include women at all,
What did the research involve?
The Almeda County Group initial selection in 1965 was a random household sample. Between 1965 and 1999, 3,077 subjects died and 1,728 were lost when trying to follow-up, either refusing to continue or just not being able to be located. The 2,123 subjects still enrolled as of 1999. Participants were to answer questions in relation to their physical activity and other lifestyle factors. A scale based off four main questions was used to gather how much physical activity they were achieving; the frequency of physical exercise, participating in active sports, taking long walks, and swimming. the participants would answer with never, sometimes, or often scoring a zero, one or two, being an eight point scale in the end. Depression was then determined using the DSM IV providing researchers with a world wide recognized definition on which to classify each participant .
|Physical activity scale||Low, medium, high|
|Education (years)||<12 / ≥12|
|Chronic conditions||≥2, 1, 0|
|Body Mass Index (BMI)||Obese (BMI,* ≥30), Underweight (BMI, <18), Normal/overweight|
|Alcohol consumption (drinks/month)||>60, 1–60, 0|
|Cigarette smoking||Current, former, never|
|No. of close friends||<3 ≥3|
|No. of close relatives||<3 ≥3|
What were the basic results?
The Authors of the study  found that low and medium physically active subjects we more likely to be depressed when compared to those with higher levels of physical activity.  Even when the authors made the adjustments in the study for age, sex, ethnicity, financial strain, chronic conditions, disability, body mass index, alcohol consumption, smoking, and social relations, greater physical activity was shown to decrease both prevalent depression "(odds ratio) = 0.90, 95% confidence interval (CI): 0.79, 1.01)" and incident depression "(odds ratio = 0.83, 95% CI: 0.73, 0.96) from 1994 to 1999." 
What conclusions can we take from this research?
Physical disability was a big focus of this study and it was shown in the results that there was a strong association between physical disability and depression as subjects in this study who reported that they were disabled, were four times more likely to be depressed when compared to those with no impairments. 
Using physical activity for the prevention of not only depression but also the reduction of the development of serious chronic conditions such as diabetes or heart disease could be important as well because of the strong link between physical health and depression in old age..
Physical activity is a very positive way of maintaining and potentially preventing depression rather than going to other extents such as medication, and if results continue to be positive this will be helpful for practitioners and other professionals being able to advise patients about physical activity and the benefits it can have on depression.
Depression is an illness with several factors that can influence the onset of it, in the study above the factor of genetics and gene expression were not considered. .
Further research should be conducted with a better representative sample of more recent times so the data collected can be more related to the general population. More exact measures should be taken when recording physical activity and other factors that were apart of the study.
It is important to remember that depression is not definite if any of these factors apply, professional advice should be found if there is any concern.
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