Effect of Walking Exercise with Breathing Control on the Degree of Shortness of Breath, Anxiety, and Depression in COPD: A Systematic Review

Introduction: Chronic obstructive pulmonary disease (COPD) is a high disease burden and negatively impacts the bio-psycho-social well-being of patients, such as anxiety, depression, and shortness of breath. Anxiety and depression can increase morbidity and worsen the condition and health status of the patient. This systematic review aimed to analyze the effect of walking exercises with breathing control on the degree of shortness of breath, anxiety, and depression in COPD patients19-related lung fibrosis to improve quality of life and prevent further lung damage. Methods: The data sources were taken from EBSCO, PubMed, and ProQuest using related keywords. Articles were selected using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) diagram method Results: Ten articles in this systematic review obtained three intervention categories: 1) intervention combined walking exercises with breathing control can be performed 30 minutes per session 2-3 times a week; 2) walking exercise intervention is performed thrice a week for 30-45 minutes per session; 3) breathing control exercise intervention is performed 10-30 minutes with a duration of 2 times a day in the morning and night or can be performed three times a week. Those three intervention categories significantly reduced the degree of shortness of breath, anxiety, and depression in COPD patients Conclusion: Findings from this systematic review suggest that walking exercise intervention in COPD patients can help reduce the degree of shortness of breath, anxiety, and depression


Chronic obstructive pulmonary disease (COPD)
is a chronic respiratory tract disease that is potentially fatal and non-reversible airway disease. COPD is characterized by symptoms of small airway airflow obstruction and lung parenchymal damage, generally characterized by inflammation of the lungs due to air pollution and harmful gases. 1 The World Health Organization (WHO) estimated that by 2030 COPD will be the third leading cause of death in the world, and currently, 64 million people live with COPD, and three million people die from COPD. 2 The United States (US) prevalence rate for COPD ranges from 10-21%. In Europe, the prevalence of COPD is 3% in the Netherlands and 26.1% in Austria. The estimation of COPD prevalence varies widely in Asian countries, with the highest at 6.7% in Vietnam and Singapore and the lowest at 3.5% in Hong Kong. 3 *Corresponding author: oritasatria11@gmail.com that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious

LITERATURE REVIEW
Based on data from the Global Burden of Disease Study (GBD), it is stated that 5% of all deaths in the world are due to COPD, with an estimated 3.17 million deaths occurring in 2015 and 251 million COPD cases in 2016. Low and middle-income countries account for more than 90% of COPD deaths. In the past 30 years, the death rate associated with COPD has doubled, implying that the health care system is failing to address the problem. 4 COPD is a high disease burden and negatively impacts patients' bio-psycho-social well-being, such as shortness of breath, anxiety and depression, and quality decreasing of life. Anxiety and depression can worsen the health condition of COPD patients, resulting in increased morbidity. 5 Shortness of breath is a widespread and most troublesome complaint in COPD patients because it causes the inability to get air to breathe regularly. 6 It causes an increase in respiration rate. The brain responds to shortness of breath by sending signals that it is difficult to breathe. This response can trigger anxiety and panic attacks in patients with COPD. Panic attacks and anxiety can also cause breathing difficulty. Because these symptoms affect each other, COPD patients often get stuck in the cycle, where breathing difficulty triggers anxiety, making breathing harder for COPD patients. 7 Walking exercises can reduce shortness of breath, symptoms of depression and anxiety, increase recovery time after an acute exacerbation event, and improve quality of life. Training can be performed 2-3 times weekly for 10-30 minutes. Walking begins with slow steps, which are then slightly increased each day. 8 Breathing exercises can help to calm the respiratory tract to warm and humidify the inhaled air and simultaneously filter the air to become cleaner and return the oxygen to the body faster. This breathing pattern exercise can be performed for 5-10 minutes. 9 This systematic review analyzed how walking activities with respiratory control reduce breathlessness, anxiety, and depression in COPD patients.

METHODS
This systematic review used a narrative descriptive analysis of some of the main findings from research articles that discussed the effect of walking exercises with breathing control on decreasing the degree of shortness of breath, anxiety, and depression in COPD patients. Preferred reporting items for systematic review and meta-analyses (PRISMA) guidelines were used as a standard in reviewing and selecting research articles to improve the quality of selecting research articles in a systematic review consisting of four stages. 10 The population, intervention, comparison, and outcome (PICO) model was also used to determine inclusion and exclusion criteria. PICO is a framework that can help construct comprehensive foreground clinical questions and guide systematic reviews. 11

Inclusion and Exclusion Criteria
Inclusion and exclusion criteria are described in Table 1.

Sources of Search Information
This study used a database of international health journals as a source of articles consisting of EBSCO, ProQuest, and PubMed with a publication period of 1 January 2015 to 31 December 2020. The search strategy used keywords that match the research topic, using the equivalent word from the Medical Heading Subject (MeSH) and combining it with the standard Boolean operators (And and Or). The keywords used include "Walking Exercise" AND "Breathing Control" AND "Shortness of Breath" AND "Anxiety and Depression" AND "Cronic Obstructive Pulmonary Disease (COPD)".

Article Selection
The PRISMA method was used for the process of selecting research articles. The first stage was identifying and combining research articles from all search sources in the database. The second stage was screening, selecting articles based on the title and abstract, and then adjusting to the inclusion and exclusion criteria. The third stage was eligibility based on the research article's full text and also by the inclusion criteria. The fourth stage was the included stage; articles that had been reviewed in the full text would be included at this stage because relevant research articles had been obtained with the topic and research title for the systematic review. 12

Quality Assessment
The quality of the article was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal guideline as an instrument for assessing the quality of the methodology and determining possible biases in the design, implementation, and analysis of a study. The JBI Critical Appraisal instrument is also adjusted to the type of research used, namely for quasi-experiment and randomized controlled trials. 13

Respondent Characteristics
The total number of respondents from 10 research articles was 578 COPD patients. Most respondents in articles with RCT design were 150 respondents. 17 Of the ten articles in this systematic review, it was found that the respondents were patients with COPD stage I, II, III and IV with stable conditions. The average age of the respondents was 30-70 years old, male, high school education level, and had a smoking history. The research was conducted in various countries, including two from Brazil and one article each from Taipei, the Netherlands, Egypt, Denmark, Colorado, Nepal, China, and Australia.

Intervention Characteristics
This systematic review categorized three intervention programs from the ten articles. First, the intervention of a combination of walking exercises with breathing control consists of breathing-based walking exercise, 5 combined exercise training and a home-based walking program is given, 13 and aerobic training combined with respiratory muscle stretching, 14   Based on Table 3, nine articles of RCT design were obtained, with five good-quality articles. 14,16,18,20 The other four articles on RCT design were of sufficient quality. 5,13,15,19 Whereas for research articles with a quasiexperimental design, one article was obtained with good quality. 6 Based on the results of the quality assessment of the article, it was found that the risk of bias could be minimized.

Main Results
Interventions from ten research articles can be

Risk of Bias
The research articles still have the possibility of a bias because, in research articles that used RCT design, four articles did not include blinding techniques, 5,13,15,19 and there was one article that did not mention ethical approval in writing. 15

DISCUSSION
The interventions from the ten research articles can be categorized into three intervention programs. First, a combination intervention of walking exercises with breathing control has a significant effect on reducing the degree of shortness of breath, anxiety, and depression.  15 According to the guidelines from ACSM, it is recommended that physical activity associated with a decrease in the degree of shortness of breath is by doing 1-3 exercise sessions with a duration of 8-12 repetitions and should be performed with a frequency of 2-3 times every week for 30-60 minutes. 22 According to ASCM, 21 walking exercises in COPD patients can increase oxygen demand, reduce shortness of breath and anxiety, and increase physical activity in COPD patients. Exercise can be increased according to the patient's ability. During breathing exercises, by walking, there is an optimal exchange of oxygen and carbon dioxide, thus it can make adequate ventilation, and the degree of shortness of breath is reduced.
Finally, the category of respiratory control intervention provides significant results that can help reduce shortness of breath and anxiety in COPD patients.
Breathing control exercises are performed 10-30 minutes per session, two times a day, morning and evening, or three times a week. Based on the Guideline on Breathlessness-Shortness of Breath, breathing technique exercises are important to reduce breathlessness in patients and are an important part of a comprehensive pulmonary rehabilitation program for COPD patients. 9 In a study by Matos-Garcia, et al., 23 breathing control that is performed regularly can improve respiratory muscle function, maintain lung elasticity, and improve ventilation function.
Several studies use mMRC and Modified Borg Scale (MBS) measuring instrument to measure the degree of shortness of breath, which consists of five questions with five types of assessment criteria ranging from grade 0 to 4. HADS was used to measuring the degree of anxiety and depression with good validity and reliability values consisting of 14 statements, both positive and negative, seven statements assessing anxiety, and seven statements assessing depression. Follow-up was performed by re-measuring the degree of shortness of breath, anxiety, and depression after the intervention administration for a period of up to 6 months. 18 Limitations in the ten reviewed studies included using an RCT design that did not use the blinding technique and the follow-up time of only two months for measures of shortness of breath, anxiety, and depression.

Further Research Suggestions
Further research is still needed, and the application of blinding techniques and the use of a control group needs to be conducted to strengthen the research results. The use of other interventions as a comparison needs to be performed to see which intervention is more effective. The follow-up time for the results of the intervention also needs to be considered and added to see the extent of its effectiveness.

Implications for Practice
Based on the findings, it supports the implementation of non-pharmacological intervention as an important comprehensive pulmonary rehabilitation program for COPD patients. This nursing action can be conducted by nurses collaborating with other health teams, such as physiotherapy, to achieve maximum results. The implementation of this intervention can be used as a routine activity that must be performed by patients either at the hospital or at home.

CONCLUSION
The interventions of the ten research articles reviewed in this systematic review can be categorized into three types of intervention groups, including the combination of walking exercise with breathing control, walking exercise, and breathing control exercise. These three intervention categories that focused on COPD patients were able to provide significant results in reducing the degree of shortness of breath, anxiety, and depression. This systematic review can also be used as a pulmonary rehabilitation program for COPD patients because it provides significant results in reducing the degree of shortness of breath, anxiety, and depression.
For further research, it is expected to use the application of blinding techniques in the research.

Conflict of Interest
The authors declared there is no conflict of interest.