Exercise as it relates to Disease/Daily physical activity and exercise as it relates to COPD

This WikiBook is a critique of the article: Zwerkin M, Palen J, Valk P, Brusse-Keizer M, Effing T. Relationship between daily physical activity and exercise capacity in patients with COPD. Respiratory medicine. October 22, 2012; Volume 107, issue 2: p242-248.

What is the background to this research?
Chronic Obstructive Pulmonary Disease (COPD) is a condition that targets the lungs and is one of the of the main causes of worldwide morbidity and mortality. It is described as "chronic airflow obstruction that is progressive and only partly reversible". Potential risk factors linked with COPD include tobacco smoking, age, and environmental and occupational exposure. Treatments and or managements to prevent the casual decline in health associated with COPD involve pharmacological interventions, oxygen therapy, and life-style interventions such as exercise.

The chosen study was conducted for the main purpose "to investigate the relation between daily physical activity levels and exercise capacity in patients with COPD". 159 patients were involved in the study and had a clinical diagnosis of COPD by the definition of GOLD (Global Initiative for Chronic Obstructive Lung Disease).

This research is critical as COPD is one of the main causes of worldwide morbidity and mortality. Stated in a 2015 study, by Hillas et al., "The World Health Organisation estimates that COPD will be the third most common worldwide cause of death and disability by 2030". COPD is also linked with other chronic illnesses and patients with COPD have a high chance of obtaining them.

Where is the research from?
The experiment was conducted in the Netherlands at the Medisch Spectrum Twente, the hospital of the city Enschede. The corresponding author of the study is Marlies Zwerink, who works at the Medisch Spectrum Twente alongside three out of the four remaining authors of the article. The article had been published by the Respiratory Medicine Journal in 2012, an internationally reputable source, and was funded by the Netherlands Asthma Foundation.

What kind of research was this?
The study conducted a randomised controlled trial throughout the experiment, therefore patients were randomly assigned into a control group or a community-based physiotherapeutic exercise program (COPE-active). This is a strength to the study as randomised controlled trials are an essential way to collect data and to remove selection bias. As stated by a 2003 article, by Brighton et al., "randomisation is the only method for controlling for known and unknown prognostic factors between two comparison groups".

What did the research involve?
159 patients, with a mean age of 63.6 +/- 7.9 years, clinically diagnosed of COPD were included in the study. 80 of those patients being randomised to the COPE-active group and 79 being randomised to the control group. All patients attended four self-management sessions with the main aim of changing their behaviour towards exercise by providing information about the disease. The COPE-active program was split into two different periods, the first one being a compulsory 6-month period where patients trained three times per week. The second period being an optional but recommended 5-month period where patients were encouraged to train two times per week. The training sessions consisted of cycling, walking, stair climbing, and resistance training.

Prior to starting, exercise intensity levels for each patient were determined by obtaining baseline results of the incremental maximal cycle ergometer test and the incremental shuttle walk test (ISWT). Between 7 and 12 months the ISWT and the endurance shuttle walk test (ESWT) were performed to see the relation between daily physical activity and exercise capacity. Daily physical activity was measured by the use of pedometers and patients were instructed to "note the number of steps in a daily diary, at baseline, 7, and 12 months".

The methodology implemented shows both strengths and limitations throughout the study. The sample sizing used showed benefits as a large sample size can provide more accurate results. A systematic review, by Bravata M et al., stated that pedometer use has been shown to have benefits. But whether these benefits progress long term after the experiment is over is yet to be determined. However, a limitation was found with patients having to note their number of steps daily as self-reporting can result in bias or human error.

What were the basic results?
Within the first 7 months the results expressed that ISWT distance, ESWT distance, and ESWT time were shown to be moderately associated with improvements between daily physical activity and exercise capacity (p <0.01 for all). After 12 months the ISWT distance and change in steps per day were the only two variables that showed any statistical significance for improvements between daily physical activity and exercise capacity. Change physical activity and change exercise capacity in the control group was deemed "negligible and not significant".

What conclusions can we take from this research?
Although there were associations found between daily physical activity and exercise capacity, they were only moderate. These results show daily physical activity can increase exercise capacity in patients with COPD, although future research is needed into what tools are best suited for this relationship. The study design has benefits considering the use of randomisation, a large sample size, and pedometers. A limitation has been stated due to the use of self-reporting throughout the study.

Practical advice
Prior to participation in exercise a pre-screening form should completed and overseen by a health professional. A pre-screening form is used to rule out individuals with any known diseases or disease like symptoms to ensure their safety.

Patients diagnosed with COPD should attend self-management sessions with the aim to increase knowledge about consequences of bad behaviour, benefits of good behaviour, and providing skills to manage different issues with the disease.

Further information/resources
Adult Pre-Exercise Screening System (APSS) Screening Tool and APSS User Guide can be found here.

Journal article providing information about exercise and COPD can be found here.

Journal article providing practical recommendations for exercise in patients with COPD can be found here.