Exercise as it relates to Disease/Effects of physical training on land and in water on cardiorespiratory adaptation in COPD patients

This Wiki page is a critique of the research article: Cardiorespiratory Adaption of COPD Patients to physical training on land and in water (J. Perk, L. Perk, C. Bóden, 1995).

For the purpose of this wiki page, Chronic Obstructive Pulmonary Disease will be abbreviated as COPD.

This critique is purposed to be assessed under the Health, Disease & Exercise unit of The University of Canberra, written September 2020.

What is the background to this research?
The study was conducted to investigate the implementation of physical training in water in comparison to training on land and determine whether the activity would be 'feasible and safe' for patients diagnosed with Chronic Obstructive Pulmonary Disease. Contextually, the definition of COPD by the European Respiratory Journal in 1995 was "a disorder characterised by reduced maximum expiratory flow and slow forced emptying of the lungs due to varying combinations of diseases of the airways and emphysema". While previously COPD was alternatively termed as 'bronchitis' or 'emphysema', present studies determine these diseases as co-factors rather than aliases, as these conditions along with lifestyle choices (e.g; cigarette smoking) trigger an inflammatory response that causes the airways to constrict. Recent studies detail a more specific insight into the characteristics of the disease, defining the term 'phenotype' in the realm of COPD as a "a single or combination of disease attributes that describe differences between individuals with COPD as they relate to clinically meaningful outcomes” . Thus, the individually progressive nature of COPD is now more explicitly outlined.

Considering COPD is characterised by multiple different respiratory diseases with varying levels of severity, the study was undertaken by 20 patients without pre-existing cardiac failure or hypoxaemia. Parameters such as these indicate the lack of predetermined knowledge obtained in regards to aquatic exercise by European health systems at the time, resulting in determining a small population of subjects that had no cardiovascular issues or other illnesses that were present as a consequential progression of COPD. Establishing grounds to conclude that COPD patients could safely train in water and benefit from doing so in ways that they may or may not from training on land was particularly important for the way present rehabilitation services produce exercise programs for patients.

Where is the research from?
Joep Perk, one of the three researchers involved in the execution of this study, has since followed on to specialize in cardiology and health sciences as a professor at the Linnaeus University in Kalmar, Sweden. The study's location was Oskarshamn District Hospital, Sweden, where Perk was in close correspondence to the Department on Internal Medicine. It was then published by the European Respiratory Journal in October 1995 after revision from the European Respiratory Society, an organisation whose membership now reaches across 140 countries. While the study had been published by the ERS, there was no previous contribution made towards the authors by a sponsor concerned with achieving a specific outcome or result, suggesting there was no bias driving the execution of the experiment.

What kind of research was this?
A quasi-experimental study design was implemented across a two-stage process over the experiment. The first stage saw subjects engaging in exercise on land, while the second stage saw them them train in water. Before each stage, quantitative data regarding specific cardiovascular and respiratory measurements was collected, whereas both quantitative and qualitative data was collected during the training regime. In both occasions, the groups had not been divided or randomised. This is the greatest limitation to the study as lack of randomisation tends to limit the "ability to conclude a causal association between an intervention and an outcome"

What did the research involve?
20 subjects aged 62-76 years diagnosed with COPD were assessed in the study, all of which had an FEV1 to FVC ratio of less than 70% prior to the consumption of terbutaline (used as a bronchodilator for asthma symptoms). During the first stage, participants engaged in physical training on land involving three submaximal upper body exercises. These would be performed for three minutes each, followed by two minutes rest after each round, totalling 15 minutes. If a patient was to experience developing an arrhythmia, having their oxygen saturation fall below 85% or any discomfort, the training would cease for that participant. Before proceeding to the second stage, the subjects were given 10-15 minutes rest time to recover. The second phase involved the same exercises and timing for participants to perform except the experiment would require them to be submerged in water up to their necks in a training pool while harnessed to a hydraulic chair. For both stages, the following measurements were taken:

Prior to Exercise
 * Oxygen Saturation                                                                                                                                                              * Heart Rate
 * Breathing Frequency
 * Blood pressure

During Exercise
 * Oxygen Saturation
 * Heart Rate
 * Breathing Frequency
 * Blood pressure
 * Rated perceived Exertion using the Borg Scale

This methodology is appropriate to the study as it ascertains meaningful data that allows for suitable comparison of results for each stage due to consistency of procedural execution and measurement amongst subjects. Despite this, having only an elderly population limits the study's results to translate across different ages of people diagnosed with COPD. It allows for reliability within the study, though validity in relation to the broader COPD population is questionable.

What were the basic results?
At rest
 * Oxygen saturation, heart rate and breathing frequency were not notably affected in the instance of either stage.
 * Systolic blood pressure dropped by 9% in water, while diastolic pressure dropped by 7%, resulting in a decrease of 7% in rate pressure product.

During Exercise
 * Heart rates did not return to normal as quickly or efficiently on land as they did in water post-exercise.
 * Oxygen saturation saw a 2% fall in one of the three exercises in water, whilst others were unchanged.
 * RPE for effort during horizontal exercises in water was higher, as was dypsnoea.
 * Participants with poorer lung function experienced less loss in oxygen saturation in water. For these patients, systolic pressure on land was lower, as well as diastolic in water.

What conclusions can we take from this research?
The study's results conclude that all participants subject to submaximal aquatic exercise experienced no adverse events or experiences during engagement, deeming it feasible and safe. Comments in the discussion seem to describe aquatic exercise to be preferred over training on land, however we must take into consideration that this study was aimed to determine whether or not training in water is safe to COPD patients, rather than it being more beneficial. This is individually subjective, and it is important to note that COPD sufferers with more severe symptoms or associated diseases need to be assessed more critically before engaging in aquatic activities due to factors including swimming ability, exercise type and frequency.

Practical advice
People diagnosed with COPD should be assessed by a general practitioner before gaining advice or coaching from a health professional when engaging in physical training. Aquatic training can offer these people a way to exercise without significantly raising blood pressure or lowering oxygen saturation as long as they are guided by an experienced physiotherapist (or another health practitioner) and still reap the physical and psychological benefits of exercise. Trainers should have experience in or at least be aware of the hazards that may present themselves during training in water in regards to their patients experience in swimming, water depth, and procedures that must be followed in the event of someone potentially drowning.

Further information/resources

 * Asthma and Swimming
 * COPD Evidence and Implications
 * Pulmonary Rehabilitation for COPD Patients in Primary Care