Effects of Aerobic Exercise on Patients with Mental Illness in a Veterans Inpatient Psychiatric Unit : A Review of the Literature

Mental illness continues to be a leading cause of stressor especially for veterans in the United States. These problems are affecting the role functioning and relationships. The purpose of this review was to explore extensive literature on the benefits of aerobic exercise that lead to non-pharmacological interventions to help patients who suffer from mental illness in a veterans hospital inpatient mental health unit. Patients admitted to inpatient mental health units have a diagnosis such as schizophrenia, bipolar disorder, major depression, or schizoaffective disorders. They should also meet the diagnostic criteria of suicidal or homicidal ideation. Sometimes it may be a veteran who is unable to care for self or needs medical supervision. Upon conclusion of the literature review, evidence has shown to provide significant data supporting the benefit of aerobic exercises.


Introduction
A review of the literature was conducted to investigate the benefits of introducing aerobic exercise to veterans in an inpatient mental health unit and the possibility of reducing symptoms of mental illness.The World Health Organization ([WHO], 2003) reports indicate that mental health is a growing issue worldwide, with more than 450 million people suffering from a mental illness.Schizophrenia and major depressive disorders are in the top 10 mental illness diagnoses (Oertel-Knochel et al., 2014) and is known to effect role functioning and relationships negatively for both the individual, loved ones, and society (Mojtabai, 2011).Exercise may help the veteran reduce symptoms of mental illness (Carter, Callaghan, Khalil, & Morres, 2012).
Aerobic exercise can be used to help reduce psychopathological or abnormal behavioral symptoms while improving cognitive ability in people with mental illness (Oertel-Knochel et al., 2014).Physical exercise has been shown to increase neurogenesis and develop neuroplasticity and therefore increasing cognitive functioning (Oertel-Knochel et al., 2014).Furthermore, aerobic exercise has been shown to increase the prevalence of important growth factors including glucocorticoids, brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor ([VEGF], Oertel-Knochel et al., 2014).Growth factors such as VEGF are essential in the growth of new capillaries to increase neuroplasticity that positively affects cognitive ability and mood that will, in turn decrease the symptoms of mental illness.Many people suffer from mental illness and veterans are at high risk for mental illness (Pols & Oak, 2007).
Veterans are prone to mental health issues with exposure to combat, conflict, death, carnage, chronic pain, and separation from loved ones (Vazan, Golub, & Bennett, 2013).Participating in multiple acts that are threatening to one's life can potentially lead to mental health problems such as in the veterans (Pols & Oak, 2007).Aerobic exercise could help veterans better cope with their mental health disorders, be more productive in their lives, their relationships with others, and in the society.
Veterans on an inpatient mental health unit may benefit from regular aerobic exercise as an adjunct intervention to their therapy.On an inpatient unit, most of the veteran's day is filled with therapy, eating, and sleeping leading to a sedentary lifestyle.Physical exercise could be used as an intervention to distract the veteran and teach effective coping strategy for dealing with mental illness.Therefore, the purpose of this literature review was to explore extensive literature on the benefits of aerobic exercise that lead to non-pharmacological interventions, to help veterans who suffer from mental illness in an inpatient mental health setting.

Sample Sizes of Studies
Studies included sample sizes from (N = 9) the smallest sample (Powers et al., 2015) to (N = 200) the largest sample of subjects (Pfaff et al., 2014) giving a mean sample size for the review of 64.2.Some studies had an even representation of male and female subjects while others had skewed numbers of males (McArdle et al., 2012) and females (Powers et al., 2015).Other sample focus was at the client and clinicians (Browne et al., 2016).Mental illness diagnoses were a focus of the sample groups for the reviewed studies, which included depression or major depressive disorder (MDD), anxiety, schizophrenia, bipolar disorder, and posttraumatic stress disorder (PTSD).Six of the articles were related to depression and MDD (Bonsaksen & Lerdal, 2012;Browne et al., 2016;McArdle et al., 2012;Oretel-Knochel et al., 2014;Pfaff et al., 2014;Toups et al., 2017) and one PTSD (Powers et al., 2015).Exercise as an intervention was found to be beneficial in six studies for treating mental illnesses (Firth et al., 2016;McArdle et al., 2012;Oretel-Knochel et al., 2014;Powers et al., 2015;Strassnig et al., 2015;Toups et al., 2017) along with other related subthemes.

Measurement Tools Used in Studies
Measurements of major variables were completed with some strategies that included multiple measurement tools.The Diagnostic and Statistical Manual is a tool that was used to measure the severity of depression (Pfaff et al., 2014).Other measurements of anxiety and depression were measured with the hospital anxiety and depression scale ([HADS], Bonsaksen & Lerdal, 2012).Depression measurements were conducted with the motivation energy inventory ([MEI], Bonsaksen & Lerdal, 2012) and Center for Epidemiologic Studies depression scale ([CES-D], Smith-Marek et al., 2017).Trauma was measured with the life event checklist for DSM-5 (LEC-5).Measures of cognitive training and performance were captured by using the brief assessment of cognition in schizophrenia (BACS), which would also be used to help measure items such as symbol coding (Oertel-Knochel et al., 2014).There were many other forms of measure and measurement tools found in the ROL that are listed in Table 2.
Two studies dedicated to depression found opposite results with the intervention of exercise.Both studies were not located in an inpatient unit.One study was focused on an age group that was 50 years of age and greater and solely based at the subject's home (Pfaff et al., 2014).While the other study that had more positive results were using an age group ranging from 18-70 years of age, was well supervised in a training facility for the initial two weeks, and then continued the intervention at home (Toups et al., 2017).Subjects did poorer with the intervention solely in their home and supervision from a booster telephone call.The lack of observation perhaps led to the lack of intensity of the exercise interventions, which may have had an impact on the results.However, exercise was shown to have improvements in motivation as well as depressive severity that led to better social motivation for subjects (Toups et al., 2017).The exercise was also found to be beneficial in the enhancement of functioning and cognitive abilities (Oertel-Knochel et al., 2014;Strassnig et al., 2015).
The highest results of cognitive improvements and positive mood alterations were found in studies that had the usage of a facility with a directed program (Oertel-Knochel et al., 2014;Strassnig et al., 2015).This would include the use of on staff researchers, coaches, and physiologists to help encourage subjects to exert proper energy and complete the entire workout for the day (Oertel-Knochel et al., 2014;Strassnig et al., 2015).Programs were organized at clean state-of-the-art athletic facilities, which the subjects stated helped them continue the program (McArdle et al., 2012;Strassnig et al., 2015).The structured physical activities at a training facility (McArdle et al., 2012;Strassnig et al., 2015;Toups et al., 2017) and in an inpatient setting (Oretel-Knochel et al., 2014) were found to be more effective than the unobserved home-based programs (Pfaff et al., 2014).
Outcomes of the research were positive for the promotion of exercise as an intervention for mental illness (Firth et al., 2016;McArdle et al., 2012;Oretel-Knochel et al., 2014;Powers et al., 2015;Strassnig et al., 2015;Toups et al., 2017).The act of physical fitness showed a multi-layered positive effect for people who suffer from mental illness.There was an increased sense of well-being as well as an increased motivation for social interaction and a sense of excitement for the activity and increase in self-perception (Firth et al., 2016;McArdle et al., 2012;Oretel-Knochel et al., 2014;Powers et al., 2015;Strassnig et al., 2015;Toups et al., 2017).Exercise, in particular, aerobic exercise, can influence the BDNF plasma levels in the body and have a profound positive impact on PTSD symptom management (Powers et al., 2015).Other factors that influence a better quality of life were an increase in cognitive skills including working memory, verbal learning, and visual learning in subjects with schizophrenia (Oertel-Knochel et al., 2014).Exercise lowered symptoms of depression and anxiety while increasing daily functioning abilities even in inpatient adults with severe mental illness (Bonsaksen & Lerdal, 2012).Other important outcomes are subject perspectives of the intervention and their perceived barriers to exercise (Browne et al., 2016).Some subjects found that exercise was very useful in relieving them of their daily stressors and looked forward to the activity (McArdle et al., 2012).While others in the early stages of psychosis found exercise therapeutic to their symptoms (Firth et al., 2016).

Discussion
Aerobic exercise is a beneficial intervention for people who suffer from mental illness and veterans are prone to mental health disorders with exposure to combat situations and high-stress environments (Pols & Oak, 2007).Aerobic exercise was shown to have improvements in cognition and symptom management.Exercise as an intervention for veterans' post-military with acute mental health symptoms may show decreased severity of symptoms and may also reduce the frequency of acute exacerbations of chronic symptoms.
Exercise improves plasma levels of BDNF that aids in symptom management of PTSD, which is a rising mental health symptom of veterans who are returning from combat areas (Pols & Oak, 2007).Mental health complications and symptoms are better controlled with the introduction of aerobic excise.The increased physical activity helps increase neuroplasticity helping the veteran in an acute mental health setting gain increased physiological pathways for increased neurological growth versus only using medication and therapy.Exercise can be used as a coping skill to help treat mental illness.An additional factor found to help motivate veterans to exercise was whether they were being cared for in an inpatient or outpatient setting.
The most beneficial setting in promoting active engagement in aerobic exercise was inpatient units with coaches.Coaching veterans in the inpatient mental health setting may be effective in increasing participation and gaining their feedback for program improvements.Veterans receiving mental health care may benefit from alternative therapies that help increase their level of healthy activity.Guidance to help combat the tendency for a sedentary lifestyle and antipsychotic medications increases susceptibility for weight gain as they can lead to other physical complications such as cardiovascular disease.

Limitations
There were various limiting factors found in the reviewed studies.One of which was small sample sizes with a mean sample size of 63.3.Other limiting factors found were low generalization with interventions taking place at one facility.Some studies were skewed with a dominant presence of one sex in the study.Positive bias was found in a feedback study post intervention with a qualitative study and inclusion of only the completers of the intervention.Other interventions included the non-supervised approach to implementation leading to skewed data and non-compliance.

Clinical Implications
Staff can implement exercise as an intervention for patients in an inpatient mental health setting.Appropriate assessments, facility, and clearance from providers will be necessary to ensure safety for staff and patients.Staff can designate aerobic exercise as part of the veteran's treatment plan as they progress through the acute mental illness state to recovery.This would be most effective if led by a program supervisor to facilitate the exercise activities for the inpatients.The benefit for the veteran who participates could be lifelong, as exercise is a relatively inexpensive, learned intervention that they can continue as an outpatient.

Recommendations for Further Research
Further research would benefit with the exploration of aerobic activity and its effect on veterans in the inpatient setting through to the outpatient setting.Staff researchers and veterans would benefit from the retrieval of data from veteran patients that are admitted into the inpatient mental health setting and are introduced to aerobic activity as an aspect of their treatment plan.It will be beneficial to follow their progression through to recovery and compare with a control group of usual mental health recovery care.Researchers could continue the study into the outpatient setting and monitor the rates of return to the acute mental health setting between the intervention and control group to identify if the intervention group has an improved level of mental health recovery as compared to usual care.

Conclusion
Aerobic exercise is highly recommended for patients in the inpatient setting.This would be an intervention that could aid the veteran in mental health symptom management as well as physical symptoms that may accompany the disorder.Increases in activity would have a positive effect on the veteran's relationships and socialization opportunities.The veteran will be more apt to learn positive coping skills with exercise that is inexpensive and may reduce the chance of using substances to self-medicate (e.g., alcohol) and deter them from treatment.

Table 2 .
Primary research for aerobic exercise and the effects on mental