Physical activity and pulmonary rehabilitation – A competing agenda?

The value of being physically fit is well described in the literature. The data seem to indicate that being physically active confers significant benefit. Rehabilitation interventions based upon improving physical activity (PA) and exercise capacity add value at all stages of the disease. The traditional aim of pulmonary rehabilitation has been to enhance exercise capacity, and this is reflected in the choice of commonly reported outcome measures. In the absence of directly measured PA, it is assumed that increased exercise capacity is a key mediator to increase PA. The explicit expectations of rehabilitation have altered and there is now the challenge of not only increasing exercise capacity but also PA. The 2013 definition from the American Thoracic Society/European Respiratory Society statement on pulmonary rehabilitation proposes that the aim of rehabilitation is not only to facilitate gains in exercise capacity but also to support behaviour change and the adoption of a healthy lifestyle.¹ The new definition has encouraged us to broaden in our approach and develop strategies to promote long-term adherence to health-enhancing behaviours. In the article by X, the authors describe the integration of enhancing PA alongside improving exercise capacity within the context of a pulmonary rehabilitation programme. There is an emerging literature describing the technical challenges of actually measuring and quantifying PA which have supported this endeavour, but few rehabilitation studies measuring PA have reported a successful outcome.² Other studies have reported PA interventions, which involve activity counselling (alongside a rehabilitation programme); these studies have employed a pedometer or activity monitor with either immediate feedback or feedback by health-care professionals at regular intervals with some success.³ All of these studies tend to be small and not powered to detect changes in objectively measured PA.

The challenge of improving PA is complex and in reality is beyond the health care system alone. Many models have been proposed that describe PA and important factors that may either enhance or discourage PA. As health care professionals, we can realistically focus our efforts’ on the individual and their interaction with their carers and their environment, but it is the role of the government to address policy and wider environmental issues to facilitate and sustain local PA opportunities.

The article by Cruz in this issue (191-198) describes in some detail the challenges of integrating PA interventions into a traditional rehabilitation programme. One might argue that this represents a conceptual challenge for those involved in rehabilitation and one worthy of consideration. Improving exercise capacity is not the same as improving PA levels, and an improvement in exercise capacity does not necessarily lead to an improvement in PA and vice versa. The rehabilitation programme described by the authors offered a typical exercise training programme, the intensity was set at 60–80% of the average walking speed achieved on the 6-minute walking test, alongside strength and balance training over a 12-week period, three times per week. A ‘blinded’ activity monitor was given to patients at three time points for 7 days, and they received feedback for 15–20 minutes in the following weeks. This was just two sessions, as the final monitoring was upon graduation from the programme. The advice was given in groups and received general advice about PA targets (either 7000 steps/day, 30 minutes/day of moderate activity or 20 minutes/day of vigorous activity both in 10-minute bouts) and also individualized. Importantly, this feasibility study also collected data on the acceptability of this approach to the participants. A small majority of patients were bothered by the device, in terms of the wear time and the general inconvenience; however, a similar proportion also reported that wearing the device made them walk more! The group reported a significant increase in steps achieved, albeit in a small number of participants. There were also important gains in the 6-minute walking test. It should be noted that these patients were less disabled than those commonly seen in rehabilitation programmes and at baseline were able to accumulate over 8500 steps/day.

Self-management is a difficult term to define, but a comprehensive and supported self-management programme aims to improve the overall well-being of an individual, and a component of this may be exercise capacity and or PA. There have been a few instances of PA being monitored within self-management studies. The COPE study⁴ is a supported self-management programme that offered an extended period of supervised exercise training; this intervention reported an improvement in PA, reported as steps and a smaller improvement in walking distance.

PA is clearly important to patients with chronic obstructive pulmonary disease though it is not the main outcome for rehabilitation, and the primary aim of improving exercise capacity does not necessarily result in a proportionate increase in PA due to all the other influencing factors and the nature of the package itself. PA programmes do not directly improve exercise capacity necessarily but may be a by-product of being more active.

It may be that we can take a different approach using a more comprehensive data set that can be collected at baseline to inform the components or sequence of interventions. Figure 1 comprises two simple baseline variables of exercise capacity and PA. The figure has been modeled on the new Global Initiative for Chronic Obstructive Lung Disease guidelines.⁵ The axes identify high and low PA and high and low exercise capacity. Using predicted normal values, it is possible to identify participants who might benefit from an intense rehabilitation programme or those needing support improvements in PA. This may include a conventional package of rehabilitation, for those with low exercise capacity, independent of their PA levels.

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Figure 1. Proposed stratification of interventions based upon measurements of physical activity and exercise capacity for individuals with chronic respiratory disease.

Alternatively for those with acceptable levels of exercise capacity, an intervention targeting behaviour change may be more appropriate. The precise nature of these interventions is yet to be explored and described. This is an exciting field, and doubtless over the next few years we will see plenty of data describing PA and how it can be improved potentially with the use of technology. It might be that rehabilitation in its current format is not the best fit to improve both exercise capacity and PA.