Exercise as it relates to Disease/Exercise and respiratory training on patients with chronic pulmonary hypertension

This is a critique of the research article Effect of Exercise and Respiratory Training on Clinical Progression and Survival in Patients with Severe Chronic Pulmonary Hypertension (2011).

This is an assignment for the unit of Health, Disease and Exercise for the University of Canberra.

What is the background to this research?
Pulmonary hypertension (PH) increases vascular loading on the right ventricle, which can cause electrical, mechanical and structural changes to the heart and lungs. This allows for ventricular interdependence, resulting in the unloading of the left ventricle. It is an uncommon disorder of unknown medical causes, characterized by an increase in pulmonary artery pressure and vascular resistance, often leading to failure of the right ventricle of the heart.

The definition for PH was developed in the 1998 World Health Organization meeting. PH is most commonly associated with respiratory system disorders and is classified as a pulmonary artery mean pressure, at rest, of 20mmHg or greater and is commonly due to an increase in pulmonary vascular resistance.

Physical capacity and quality of life (QoL) are often restricted for patients with pulmonary PH. Specific medical treatment options partnered with an exercise respiratory training program result in an increased exercise capacity and overall QoL for these individuals.

The aim of this study was to determine whether the benefits of exercise and respiratory training on physical capacity and QoL can be applied to a larger cohort of patients, and if an exercise program is a viable long term therapy for PH patients.

Where is the research from?
The research was conducted at the Centre of Pulmonary Hypertension, Thoracic Clinic, University Hospital in Heidelberg, Germany. This particular group of PH patients had been referred from nine different medical centres.

All patients provided written informed consent to participate in this study, which was approved by the University of Heidelberg’s Ethics Committee.

What kind of research was this?
The prospective study investigated 58 patients with severe chronic PH and right heart failure between January 2003 and April 2007, including the follow-up time of 24±12 months. The participants received respiratory training and exercise in addition to disease-targeted medication.

Inclusion criteria of participants:


 * Aged 18–80 years old
 * Classified as WHO functional class II-IV
 * Had to be stable and compensated with appropriate medical therapy at least 3 months prior to the beginning of the study

Some patients were removed from the study during the 3 month period prior to the study. The exclusion criteria of participants included:
 * Failing the baseline tests
 * Change in medication during the 3 months
 * Listed for lung transplantation

What did the research involve?
Patients were prescribed with an exercise program to partake in, for at least 15 weeks. For the first 3 weeks, all patients remained in hospital and completed the exercises in controlled, supervised conditions. At the end of the third week, patients were discharged and returned home, receiving an individualized program and a bicycle ergometer to continue the prescribed exercise.

The exercise program included:
 * Daily interval bicycle ergometer training at low workloads
 * Daily walking
 * Resistance training of single muscle groups using 0.5–1 kg dumbbells
 * Respiratory training 5 days a week
 * Psychological training to improve patients' perception of physical ability and understanding limitations

The patients' oxygen saturation and heart rate were continuously monitored throughout the exercise training and were used to adjust the intensity of the training. The program was closely monitored by physical therapists and physicians for the first 3 weeks and the amount of training at home was supervised by phone calls every 2–4 weeks after discharge.

Patients were clinically assessed at baseline, after the 3 month period, as well as 3 and 15 weeks after the commencement of exercise, followed by regular clinical visits or phone calls for 24±12 months.

The clinical assessments included:
 * A 6-minute walking test (6MWT) performed in a large hall under standardized conditions
 * Health-related QoL test, performed by the Short-Form Health Survey (SF-36)

Changes in WHO functional classification, Borg dyspnea index (6 - no exertion, 20 - maximal exertion) and gas exchange were also analyzed over the 15 week program.

What were the basic results?
It was concluded by the authors of this journal that the tests conducted at the end of the 15 week exercise program proved that:


 * There was an increase in the 6-minute walking distance of 96±61 metres, which was a greater value than that achieved with medical therapy
 * The patients resting heart rate was significantly reduced
 * QoL parameters were also improved. All patients reported that they had improved awareness of their physical abilities and limitations
 * Exercise capacity, peak oxygen uptake, anaerobic workload threshold, maximum heart rate and systolic pulmonary artery pressure improved at rest for all patients, suggesting a reduction in right ventricular work
 * The mean WHO functional class significantly improved

The researchers of this study acknowledged the time to clinical worsening and the deterioration in functional class of some of the participants during the exercise program. However, the training itself was well tolerated and there were no adverse effects or progression of symptoms in any participant.

What conclusions can we take from this research?
It has been demonstrated that carefully monitored exercise and respiratory training as a supplement to appropriate medical therapy can improve the 6-minute walking distance as well as QoL in patients suffering severe PH.

Exercise and respiratory training with PH is an effective but not completely harmless additional therapy, even in patients with severe diseases, and all exercise should be closely monitored. Many similar studies also suggest that low-dose exercise and respiratory training as a supplement to medical therapy is safe in a closely supervised setting and it may improve the exercise capacity and QoL of patients with many forms of PH.

Further research is required to determine whether exercise and respiratory training can increase the survival rate for PH patients. The only prospective, randomized trials to demonstrate a favorable impact on mortality in PH patients have been performed using continuous intravenous epoprostenol (a short-acting vasodilator of the blood vessels in the heart and lungs and an inhibitor of platelet aggregation ).

Practical advice
Participating in any form of physical activity has implications for a typically healthy individual, but this is particularly enhanced when a disease or health issue becomes evident.

Many patients that suffer severe PH as a result of COPD have an additional cause of pulmonary pressure elevation including, left ventricular disease, pulmonary embolism or sleep apnoea. This particular population of patients suffered from PH associated with a variety of different conditions. These additional health issues require individualized medication and treatment based on the patient and their medical history. This may imply that exercise and respiratory training could have adverse effects on certain patients.

A limitation of this study was the gender bias. The population consisted of 42 women and only 16 men. Another possible limitation would be the overall size of the population (n=58). Although, in the article it was mentioned that, to date (2011), there is no data available in a larger patient cohort for this particular type of research.

Further information and resources
The following websites provide useful information, fact sheets and support for patients with PH in regards to exercise:


 * Pulmonary Hypertension Association - Exercise Guidelines
 * National Organization for Rare Disorders - PH
 * Lung Foundation Australia - Rehabilitation Toolkit
 * St Vincent's Hospital, Heart Health