Exercise as it relates to Disease/Walking: A step in the right direction for COPD patients

This review was completed for the unit Health Disease and Exercise at the University of Canberra and explores the relationship between exercise and increased quality of life for Chronic Obstructive Pulmonary Disease (COPD) patients.

This is a critique of the paper: Wootton, S.L., et al., Ground-based walking training improves quality of life and exercise capacity in COPD. Eur Respir J, 2014. 44(4): p. 885-94.



What is the background to the research?
COPD is a progressive limitation of airflow into the lungs over a period of time that is essentially irreversible. Certain risk factors associated with COPD include cigarette smoke, age, environmental exposures and pollutants. Classifying the disease severity is based on the patients' symptoms, exacerbation history and a spirometry assessment, measuring airflow obstruction. An increase in the frequency of COPD exacerbations are indicative of higher disease severity. In 2020, COPD is predicted to be the third leading cause of death for populations over 45 years old. The cost on the health care system is substantial, with an estimate reportedly spending over 42 billion per annum. However, COPD also imposes significant costs to the quality of life of people living with the disease everyday. There is a specific need to optimise treatments associated with COPD, as the global burden of this respiratory disease is set to rapidly increase in the future. This current study uncovers the relationship between walking training and improvements in the quality of life for the people living with COPD.

Where is the research from?
Recruitment for this study included participants from both Perth and Sydney from pulmonary rehab outpatient referrals. As this study was conducted locally under high quality Australian standards, results obtained are particularly relevant to an Australian population.

What kind of research was this?
This study was a prospective randomised control trial. Randomised controls trials are considered effective in producing a true and accurate result following an intervention as the influence from external variants is reduced. The researchers used biased randomisation towards the walking group with a 2:1 ratio compared to controls participants. The reasoning behind this decision was to allow for appropriate follow up of results regarding maintenance 12 months after research completion.

What did the research involve?
The research was gathered from a group of participants with moderate, severe and very severe COPD. Randomisation ensued, dividing participants into either the walking or control group. The walking groups intervention involved ground based walking on a flat indoor track with supervision from an experienced pulmonary rehabilitation physiotherapist. Ideally the intervention participants attended training sessions three times weekly for eight weeks, with training gradually progressing from 30 to 40 minutes’ duration. In this group, the patients were required to walk at a pace which produced a shortness of breath score (dyspnoea) of 3-4, or more functionally, a pace where the patient could just hold a conversation. If the patient was unable to increase step length and thus speed, the addition of weights were added to increase exercise expenditure. Although rest breaks were allowed when symptoms became intolerable, this was not incorporated in the total walking training time. It was the individuals exercise tolerance and ability that guided any increases in speed or intensity, which was different for every participant. The control group however, had no exercise information provided and instead a letter which was sent to the patients GP discussing the patient’s involvement in the study regarding the intention to treat using usual medical care.

The limitations associated with this study included the lack of physiological insight and accompanied testing. It is not known what the improvements in exercise endurance or reduction of dyspnoea were specifically caused from, with decreased ventilator demand, decreased anxiety and improved neuromuscular recruitment all plausible conclusions. Furthermore as this research paper excluded people with mild COPD, the idea of ground based walking as a global treatment cannot be extended to the entire COPD population and further research and testing will need to be undertaken.

What were the basic results?
The results from this study were obtained from the outcome measures employed. The primary outcome measure, health related quality of life (HRQoL) was assessed via two questionnaires’. The Saint George Respiratory Questionnaire (SGRQ) considered symptoms, activity limitations and the impact of respiratory disease, while the Chronic Respiratory Questionnaire (CRQ) is specific to COPD and considers dyspnoea, fatigue and emotional function. The results comparing baseline and post intervention outcomes reveal significant improvements in all outcome measure domains for the walking group compared to controls. Additionally, the second aim of the study was to determine if there were any improvements in endurance and functional and peak exercise capacity with ground based walking. The outcome measures included the 6 minute walk test (6MWT), endurance shuttle walk test (ESWT) and incremental shuttle walk test (ISWT). Compared to controls, the walking group had significant improvements in the 6MWT distance and ISWT time. Furthermore, at the conclusion of the study 18% of patients in the walking group compared to only 4% of patients in the control group completed 20 minutes on the ESWT.

It is discussed that the primary outcome measure, SGRQ generated more favorable results as the questionnaire itself focused on walking related activity. In relation to the secondary outcome measure findings, although there were significant improvements for walking endurance in the ESWT, preferable results for exercise capacity measured with the 6 minute walk distance covered was minimal. It is thought that the cause of improved results may be more related to the small reduction in the control group distance post intervention, rather than any improvements in the walking group.

What conclusions can we take from this research?
The conclusions attained reveal ground based walking improves quality of life for people living with COPD. It is indicated from the intervention that while people are not able to walk faster, they are able to walk further with ground based walking training. This new found endurance is thus the critical factor for completion of activities of daily living and as a result improve health related quality of life. The findings of this study also parallel with other publications reporting that exercise is the keystone of pulmonary rehabilitation, especially with the reduction symptoms.

Practical advice
Ground based walking training for people living with moderate to severe COPD is an appropriate and resource efficient approach to improving HRQoL through walking endurance. Ground based walking provides an alternative to resource based pulmonary rehabilitation programs which involves equipment such as treadmills or cycle ergometers. Instead it offers a more simplistic, equipment free and easy to administer approach more suitable to remote areas. There were also no adverse effects reported throughout the study. This was despite the severity of the patients COPD as well as the long training sessions, thus reflecting the opportunities for this modality to be incorporated safely in the wider community.

Further information/resources
Further readings regarding COPD and the possible benefits associated with physical activity can be found in the below links.

http://lungfoundation.com.au/patient-support/copd/

https://www.dailystrength.org/group/copd-emphysema

1800 654 301 (Lung Foundation)