Exercise as it relates to Disease/Can physical activity reduce anxiety across gender and age?

This is an analysis of the journal article "Regular exercise, anxiety, depression and personality: a population-based study" by De Moor M.H.M. et al., (2006).

What is the background to this research?
Anxiety is a condition when “anxious feelings don't subside. Anxiety is when they are ongoing and exist without any particular reason or cause.” There are many causes of anxiety, including:
 * a history of mental health problems in the family
 * ongoing stressful events
 * physical health problems
 * substance use
 * personality factors

Prevalence
According to the Australian Department of Health, the 2007 National Survey of Mental Health and Wellbeing showed that anxiety disorders were “the most common class of mental disorders with one in seven (14.4%) people experiencing anxiety disorders in the 12 months prior to interview.”

There have been many studies to prove that exercise directly reduces the effects of anxiety on individuals. For example, Herring M.P. et al., (2013) found that “exercise training can improve anxiety symptoms among healthy adults, patients with a chronic illness, and patients with panic disorder and GAD (generalised anxiety disorder)”. However, there has been little research into investigating the effects of exercise on age and gender, and further research is needed to see if there is a difference in the results when comparing these factors. The research explored in this study examined this relationship in more detail.

Where is the research from?
This study was supported by the Netherlands Organisation for Scientific Research, who have been performing an ongoing study on the relationship between health and lifestyle.

What kind of research was this?
This research was a longitudinal study. The study was acted out on sets of twins and their families, completing surveys on lifestyle and health every two years from 1991-2002.

What did the research involve?
The participants had their exercise participation measured in detail through surveys. They were asked whether they exercised regularly, and if so, were then asked further information regarding the type, frequency and duration of the exercise. This information was then compiled to calculate their metabolic equivalent of task (MET) score. The participants were classified as being exercisers if they exercised at least 60 minutes per week, with a MET score of 4 or more. It should be noted that physical education accomplished at school did not count as exercise, as the focus of this study was on self-initiated exercise.

This study assessed anxiety levels, which were measured by STAI, across age groups of 5 years, with a range of 10->65.

What were the basic results?
The study found that as both males and females aged, the amount of time spent exercising decreased, while their anxiety levels increased. It was found that on average, although the differences are small, exercisers are less anxious than non-exercisers. While anxiety does affect women more than it does men, regardless of exercise, the study still found that exercise had the same impact on anxiety, irrespective of age and gender.

It was also shown that there was a spike in anxiety levels for males, starting at age 35-40, and finishing at 45-50, before dropping back down again. While this was an unusual trend compared to the other data, the anxiety levels were still lower than at the same stage for non-exercising males.

In figure 1, the % of male and female participants that exercised is shown at different ages, while in figure 2 the differing anxiety levels are shown, comparing the four categories as they age; exercising males, exercising females, non-exercising males, and non-exercising females.

How did the researchers interpret the results?
The researchers deduced that, while the differences in anxiety levels were small, this study supports the results found by similar studies. One study found that a lack of exercise was associated with depression in population samples with a broad age range (Weyerer, 1992, as cited in De Moor M.H.M. et al., (2006))., as well as in samples of both younger (Steptoe et al., 1997, as cited in De Moor M.H.M. et al., (2006)). and older adults (Strawbridge et al., 2002, as cited in De Moor M.H.M. et al., (2006)). Although these studies were not directly associated with anxiety, they can still be linked as both depression and anxiety are mental health conditions and share similar effects. However, a journal which contrasted this study found that, in adolescents, “regular exercise was associated with better social functioning, but not with less anxiety and depression” (Allison et al., 2005).

What conclusions should be taken away from this research?
While there was only a small emphasis placed on the effect of exercise on anxiety specifically, it can be concluded that exercise does reduce the effects of anxiety on individuals, regardless of age and gender. Therefore, we can apply the findings of this study in the real world by exercising for at least 60 minutes per week, with a MET score of 4 or more. By doing this, we can expect to see a decrease in anxiety levels, albeit only by a small amount. However, as the effect on anxiety levels was only a small portion of this study, more emphasis should be placed specifically on this in future studies to provide more accurate results on exercise’s effect on anxiety regarding age and gender.

What are the implications of this research?
A problem with this study was that it measured the effect of exercise on many factors, including depression, social problems, and personality traits. Because of this, there was not as great an emphasis on anxiety as there could have been, which may have resulted in a less accurate reading of anxiety levels. Also, the levels of anxiety could be influenced by the personality traits identified in the study, which may then lead to even less of an investigation into the direct effects of exercise.

Another issue found with the study were the ranges of each age group. They were set quite broadly at 5 year intervals. If the groups were separated in 1-3 year intervals, this would show a more accurate reading of anxiety levels relating to the age of participants and would allow the researchers to draw more precise conclusions.