Exercise and Mental Health: Psychological Benefits
By Eric Shamus, PhD, Stephen A. Russo, PhD, Casey Fields, BA, Geoffrey Peal, BA, Susana Quintana Marikle, MS, Royce D. Butler, BS
The health and phycological consequences of inactivity have been well documented throughout the medical and psychological literature. For example, studies have shown that people who live sedentary lifestyles carry at least twice the risk of serious disease and premature death when compared to their active counterparts.1 In addition, it has been estimated that in the United States, inactivity results in one third of all deaths from coronary heart disease, colon cancer, and diabetes.2
Today, there is growing recognition of the widespread mental malaise in the general public that is expressed through depression, anxiety, low self esteem, stress, and poor stress coping.3 However, there is far less documentation of the psychological benefits of beginning and/or maintaining an exercise program. The purpose of this document is to summarize the existing knowledge on the mental health benefits of exercise, focusing predominantly on the psychiatric conditions of depression and anxiety.
As awareness of the positive consequences of exercise increase and as treatment outcome studies continue to demonstrate stable and reliable psychological improvements through consistent physical activity, it seems only natural that cardiovascular and resistance training programs come to be viewed as a formal intervention strategy for individuals in search of natural, alternative treatments for these common psychiatric conditions.
The effects of depression can be debilitating, touching many aspects of an individual’s life. The Diagnostic and Statistical Manual of Mental Disorders IV-TR (APA); defines Major Depressive Disorder (MDD) as a period of two or more weeks during which there is depressed mood or the loss of interest or pleasure in almost all activities, including at least four of the following: changes in sleeping or eating patterns; decreased psychomotor activity; diminished energy; feeling guilty or worthless; trouble concentrating; or suicidal thoughts. 4
The U.S. National Comorbidity Survey Replication sample reports that the lifetime prevalence for mood disorders is 16 percent.5 Given the incidence of underreporting as well as the presence of those suffering from either sub-clinical levels of depression or dysthymic presentations, it is likely that many more individuals feel the impact of depressive symptoms on a regular basis. In addition to its emotional impact, depressive conditions also place a tremendous financial burden on the economy, with an estimated cost of $44 billion in the United States during 1990 alone.6
Another potentially incapacitating mental health problem is anxiety. Anxiety is defined as a state of elevated cognitive and physiological arousal that can be debilitating and cause significant interference in almost every aspect of one’s daily life.4 Although clinical presentations of anxiety are often a reaction to life stressors, they can cause significant interference when one’s reaction goes beyond the normal activation that would be expected, given a set of circumstances.7 Anxiety can come in many forms, such as panic attacks, phobias, or generalized anxiety disorder. The latter relates to most life situations and can present as a momentary increase in arousal to a specific situation (i.e., state anxiety) or a consistent, pervasive pattern of over-activation that pervades one’s daily life (i.e., trait anxiety). These forms of anxiety are among those most frequently examined by researchers and are important distinctions when considering the literature on the mental health benefits of exercise. With up to 40 million people in the United States having a diagnosable anxiety disorder each year, an abundance of research has gone into the treatment of anxiety and anxiety-based disorders.8 While many physicians prescribe anxiolytic drugs such as alprazolam (Xanax) or diazepam (Valium) to combat anxiety symptoms, little research has gone into discerning the specific effects of exercise on these conditions and/or the possible prescription of exercise to treat these clinical presentations.
Although a wide variety of options exist for the treatment of anxiety and depression, the burgeoning research into exercise and its effects on mental health suggests that exercise may very well become a viable alternative to the standard psychopharmacological and psychotherapeutic intervention strategies typically used for these conditions. Results of many studies already show a positive impact in the amelioration of depression and anxiety for those who persevere with an exercise program.
Depression
Treatment for depression includes psychotherapy, pharmacotherapy, and many other therapeutic treatment formats. Exercise and other forms of physical activity, while often not considered by health care practitioners as possible treatments for depression, appear to be a powerful and cost-effective tool.9 A negative relationship has been found between exercise and depressive symptoms, noting that the more time an individual is physically active, the less depression they tend to report.10
This notion is supported by other researchers who found that research participants who attended regular exercise classes exhibited greater reduction in depressive symptoms than participants who merely attended health education seminars.11 Although some researchers have indicated that moderate-intensity aerobic exercise leads to significantly greater reduction in depressive symptoms than flexibility training or lower-intensity aerobic exercise,12 other investigators have found that aerobic exercise at 70 percent to 80 percent of maximal intensity was as effective as pharmacotherapy in treating mild depressive symptoms.13 Moreover, studies looking at high-dose versus low-dose aerobic exercise have found that exercise alleviates mild to moderate depression, regardless of whether an individual exercises three or five times a week;12 in some situations exercise has been found to significantly reduce moderate to severe depressive symptoms.14
In terms of the financial implication, estimated medical expenditures for depressed adults who were physically active was $354 less per year than for adults who did not engage in exercise.9 Thus, increasing a patient’s exercise regimen, which constitutes a relatively low-cost intervention approach, may represent a simple, yet significant, cost-effective way to improve mental health functioning.
The positive impact of exercise in the treatment of depression has been demonstrated across a wide range of clinical populations including high school students,15 women who are pregnant,16-18 and older adults.19-21 The results from each of these studies highlight the wide-ranging effects of exercise as well as the need for physicians and mental health professionals to recognize how to best present an exercise program to obtain maximum adherence levels from their patients.
Some of the most compelling evidence for the benefits of exercise in depressive symptoms comes from studies of the brain itself. It has been suggested that the ability to decrease depressive symptoms depends upon the development of new hippocampal neurons, and several molecules in the brain may be involved in exercise-induced increases in neurogenesis in adult brains.22 More specifically, endorphins have been implicated in the survival of new neurons in the dendate gyrus of adult animals and vascular endothelial growth factor has been found to increase when humans exercise. This may lead to subsequent increases in cell numbers within the dendate gyrus.22
Exercise also increases brain-derived neurotrophic factor, which may increase the survival of new neurons in the hippocampus. 22 Lastly, it has been found that exercise increases levels of tryptophan in the hippocampus, which has been implicated in increased serotonin production and neurogenesis.22 As exercise becomes increasingly investigated as a formal treatment intervention, the work on the chemical influences of neurogenesis as a result of exercise may be taken as evidence that exercise has a direct, therapeutic effect on depressive symptoms by means of neural enhancement.
Anxiety
Similar to the depression literature, studies on individuals suffering from anxiety show significant improvement when they participate in some type of exercise program. In a large meta-analysis on the effects of both short-term and long-term exercise programs, it was revealed that both interventions had a significant impact on anxiety symptomatology.23 In the long-term exercise programs, the effect was more robust for trait anxiety reduction, particularly when the singular bout of exercise was of a longer duration. The short-term exercise programs had a larger effect on state anxiety and a similar pattern of larger gains obtained through reliance on longer exercise sessions was found here as well.7
More recently, researchers have begun to examine more specific anxiety presentations in an attempt to expand the existing literature on anxiety reduction through exercise. Individuals assigned to either a low-intensity and high-intensity aerobic exercise program showed a decrease in general anxiety symptoms as well as reduced subjective sensitivity to anxiety symptoms.24 These investigators also demonstrated that the higher-intensity group fared better as a whole, having less fear and hypervigilance for their own anxiety-related symptoms, which are often seen as precursors to a panic attack.24
In another study that sought to use exercise as a treatment for induced panic attacks, a dose of Cholecystokinin Tertapeptide was given (known to induce panic attacks), to a group of subjects that had exercised for 30 minutes over consecutive days and compared the incidence of panic attacks to a group who had not exercised regularly.25 Results showed that the subjects who participated in the exercise protocol had half the number of panic attacks as the group that was assigned to no exercise at all.25
These findings have profound clinical applications, showing that, in some cases, exercise alone can reduce the anxiety symptoms associated with panic disorder in a manner similar to the anxiolytic medications that are typically prescribed for the condition. Moreover, these studies suggest that the use of exercise in conjunction with traditional psychotherapy carries the added benefit of producing positive mental and physical health without producing side effects such as drowsiness, confusion, and fatigue that are typically associated with anxiolytic medications.24,25
Much like the literature on depression and exercise participation, a variety of physical activities have been associated with reduced anxiety symptoms. One study that examined the reduction of anxiety through yoga and Feldenkrais (which was described as a movement exercise that focuses on increasing awareness), found a significant decrease in state-anxiety scores for both “alternative” treatment modalities, along with a general increase in subjective well-being scores.26
Importance of Exercise Adherence
While health care practitioners are now recognizing that exercise can effectively combat many difficulties, many remain unaware that consistent participation in an exercise program appears to be the most important factor in obtaining those benefits. Stated another way, adherence to a prescribed exercise program is the most crucial issue when seeking positive health benefits through exercise. Because compliance represents a unique and persistent obstacle to obtaining positive exercise benefits, health care professionals must do more than simply prescribe exercise as an intervention. Instead, they must be aware of the challenges that patients face when making behavioral changes and incorporate methods that have been found to assist individuals in establishing and maintaining their new exercise habits. Ultimately, it is the tailoring an exercise program to the needs, interests, and motivational state of the individual that will best serve to foster increased compliance.
At the foundation of the exercise adherence dilemma is the concept that, when making lifestyle changes, people vary greatly in their readiness for change and tend to progress in a cyclical rather than linear fashion.27-29 Accordingly, some patients may have no intention to exercise, while others either intend to begin an exercise program soon or have already made attempts to improve their exercise regimen. Researchers have found that matching the exercise intervention form to the stage of change that an individual currently inhabits has not only successfully generated higher levels of regular exercise, but has also effectively reduced levels of non-compliance and drop-out.30,31 Therefore, practitioners who are able to quickly assess an individual’s readiness for change are more likely to assign an exercise regimen that is appropriate for that individual.
Other researchers in the exercise adherence field have found that improved compliance is more likely when professionals gain a greater understanding of the cognitive and behavioral factors that people typically rely upon when deciding whether to make behavior changes. Encouraging individuals to verbalize the subjective appraisals of the relative costs and benefits linked to exercise as well as their expected outcomes can be instrumental in understanding why individuals may be invested in maintaining the status quo.29,30
In addition, understanding “why” people need to engage in behavior change as well as the subjective confidence they have in their ability to make the proposed changes have garnered a significant amount of interest.30,32,33 More specifically, self-efficacy, which includes both a subjective assessment of one’s ability to perform a specific desired behavior as well as one’s belief about their ability to overcome the barriers to change is often viewed as a precursor to behavioral modification because it is routinely associated with the likelihood that an individual will engage in behavior change.33
Finally, enhancing a patient’s motivation to engage in physical activity has been identified as a critical factor in predicting whether people will make behavioral changes. To this end, the communication patterns employed by health care professionals have often been found to influence this process. More specifically, training professionals in the effective use of Motivational Interviewing (MI) techniques has been consistently shown to improve the rates of behavioral change in a number of clinical populations.34.35
Despite the fact that many studies have linked exercise to a reduction in both depression and anxiety, large gaps remain in the existing literature for this topic area. It is imperative that future research is directed at evaluating comparisons between the effects of exercise and other modalities, particularly traditional psychotherapeutic and psychopharmacological intervention formats. And, as more studies focusing on the mental health benefits of exercise appear in the literature, investigators should strive to determine which forms of physical exercise are best suited for reducing each psychological presentation as well as which exercise program is best suited for the various clinical populations that seek to use exercise as a formal intervention modality.
Osteopathic family physicians maintain a unique position in promoting the positive impact of exercise. The main objective of this article has been to provide a basic overview of the existing literature on the mental health benefits of exercise. Helping physicians better understand how they can influence the essential issue of exercise adherence when prescribing exercise to their patients will ultimately improve health outcomes.
Dr. Shamus is an associate profession at Nova Southeastern University College of Osteopathic Medicine (NSUCOM). He is a PhD faculty with a degree in Physical Therapy. Dr. Russo is an assistant professor at NSU’s Center for Psychological Students and is the director of the Sport Psychology Program. He has a PhD in Clinical Psychology. Ms. Fields earned a BA in psychology from the University of Central Florida and is currently a doctoral student at NSU. Mr. Peal is a 2007 graduate of the University of Michigan and is currently a trainee at NSU in the doctoral program for clinical psychology. Ms. Marikle is a PsyD student at NSU. She received her BA in psychology from Florida Atlantic University and her MA in mental health counseling from the University of Central Florida.
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