Reliability of submaximal exercise tests in patients with COPD. Chronic obstructive pulmonary disease

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review

INTRODUCTION

Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests.

METHODS

A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English.

RESULTS

Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions.

CONCLUSION

Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting.

RESPIRATORY MUSCLE STRENGTH IN IDIOPATHIC SCOLIOSIS AFTER TRAINING PROGRAM

Objective:

To analyze the impact of a physiotherapy protocol in maximum inspiratory and expiratory pressure in patients with adolescent idiopathic scoliosis (AIS) by manovacuometry. AIS may change the respiratory dynamics and the performance of inspiratory and expiratory muscles, affecting ventilatory capacity.

Methods:

Patients with AIS aged 10 to 20 years old were randomly assigned to receive an aerobic exercise-training program or no treatment. They were evaluated for respiratory muscle strength before and after the treatment period by means of manovacuometry, thorax and spine radiographs. Physical therapy exercising protocol comprised three weekly sessions including stretching and aerobic exercises during four months.

Results:

Forty five patients received physical therapy and 45 patients received no treatment (control group). The mean maximum inspiratory pressure (Pi_max) was -52.13 cm H₂0 and the maximum expiratory pressure (Pe_max) was 62.38 cm H₂0. There was a significant increase of Pi_max and Pe_max (p=0,000) in the group receiving physical therapy. There were no drop-outs and no adverse events in this study. Respiratory muscle strength, scoliosis and kyphosis degrees were not statistically correlated.

Conclusion:

Exercising is beneficial to patients with AIS, who have shown significant increases in respiratory muscle strength after physical therapy. There was no correlation between respiratory pressure and spine deformity. Level of Evidence I, High quality randomized trial.

Long-term impact of pre-operative physical rehabilitation protocol on the 6-min walk test of patients with adolescent idiopathic scoliosis: A randomized clinical trial

BACKGROUND

Monitored physical activities in patients with adolescent idiopathic scoliosis (AIS) have been shown to improve physical performance, endurance and cardiopulmonary function and may be assessed by the 6-min walk test (6MWT). We aimed to evaluate the long-term results of the 6MWT after a rehabilitation protocol employed before surgical correction for AIS.

METHODS

This prospective randomized clinical trial studied the impact of a 4-month pre-operative physical rehabilitation protocol on post-operative cardiopulmonary function and physical endurance, by using the 6MWT, in patients with AIS submitted to surgical correction, comparing them to matched controls without physical rehabilitation. Studied variables were heart and respiratory rate, systolic and diastolic blood pressure, peripheral blood oxygen saturation, Borg score, and distance walked. Patients were assessed at baseline, after 4 months of rehabilitation, and 3, 6 and 12 months post-operatively.

RESULTS

A total of 50 patients with AIS were included in the study and allocated blindly, by simple randomization, into either one of the two groups, with 25 patients each: study group (pre-operative physical rehabilitation) and control group. The physical rehabilitation protocol promoted significant progressive improvement in heart and respiratory rate, peripheral blood oxygen saturation, distance walked, and level of effort assessed by the Borg scale after surgery.

CONCLUSIONS

Post-surgical recovery, evaluated by 6MWT, was significantly better in patients who underwent a 4-month pre-operative physical rehabilitation protocol.

Relationships of Borg's RPE 6-20 scale and heart rate in dynamic and static exercises among a sample of young Taiwanese men

The objective of this study was to assess the relationship between the scores collected from Borg's rating of perceived exertion (RPE) scale and the heart rates (HR) of young Taiwanese men. Three exercises types (dynamic, partially dynamic, and static) were performed by 12 participants (six were familiar with Borg's scale and 6 were unfamiliar) under nine test conditions of three load levels for each exercise. The effect of familiarity on the relationship between RPE and HR was also examined. The results showed that the familiarity of the participants regarding the Borg's scale did not affect the scores. The relationship between Borg's RPE 6-20 scale and the HR values during dynamic exercise was described by the regression equation HR = 8.88 x RPE + 38.2 (beats/min). The HR had lower correlations with RPE values when the participants performed both partially dynamic and static exercises. The findings may serve as a reference when using Borg's RPE scale to evaluate the physical exertion of young Taiwanese men.

Symptom cluster, healthcare use and mortality in patients with severe chronic obstructive pulmonary disease

AIMS AND OBJECTIVES

To examine how subgroups of patients with chronic obstructive pulmonary disease, identified by ratings of symptoms (dyspnoea, anxiety, depression and fatigue), affect healthcare use and mortality.

BACKGROUND

People with chronic obstructive pulmonary disease often experience multiple symptoms. The importance of multiple symptoms and symptom clusters has received increased attention. However, little is known about symptom clusters and their effect on healthcare use and mortality in this population.

DESIGN

Descriptive cross-sectional study.

METHODS

This secondary data analysis used data from the National Emphysema Treatment Trial. Participants (n = 597) had severe chronic obstructive pulmonary disease. Descriptive and inferential statistics were used to analyse the data that were drawn from structured interviews, questionnaires and clinical measures.

RESULTS

Three subgroup clusters emerged based on four symptom ratings. Mean age, proportion with higher education, proportion using oxygen, disease severity, exercise capacity and quality of life differed significantly between subgroups. Participants with high levels of symptoms used healthcare services more and were more likely to have died at the five-year follow-up than those with low levels of symptoms. Symptom cluster subgroups had more significant relationship with mortality than single symptoms.

CONCLUSION

Patients with high levels of symptoms require greater clinical attention.

RELEVANCE TO CLINICAL PRACTICE

Understanding subgroups of patients, based on symptom ratings and their adverse effect on outcomes, may enable healthcare providers to assess multiple symptoms and identify subgroups of patients at risk of increased healthcare use and mortality. Targeting modifiable symptoms within the cluster may be more beneficial than focusing on a single symptom for certain health-related outcome.

Subgroup analysis of symptoms and their effect on functioning, exercise capacity, and physical activity in patients with severe chronic obstructive pulmonary disease

BACKGROUND

Little is known about symptom clusters and their effect on outcomes in people with chronic obstructive pulmonary disease (COPD).

PURPOSES

To determine whether subgroups of patients with COPD could be identified by symptom ratings, whether they differed on selected demographic and clinical characteristics, and whether they differed on functioning, exercise capacity, and physical activity.

METHOD

Subjects with severe COPD (n = 596) were drawn from the National Emphysema Treatment Trial dataset. Data were drawn from questionnaires and clinical measures.

RESULTS

Two subgroup clusters emerged from four symptoms. Mean age and the proportion of participants with higher education, higher income levels, and using oxygen at rest were significantly different between subgroups. Participants with high levels of symptoms had lower functioning and decreased exercise capacity. Symptom cluster subgroups were significantly associated with social functioning.

CONCLUSION

These findings suggest that screening for high levels of symptoms may be important in patients with severe COPD.

The repeatability of submaximal endurance exercise testing in cystic fibrosis

Submaximal endurance cycle ergometer exercise tests are used to measure the efficacy of an exercise intervention, but the repeatability of these tests in patients with cystic fibrosis (CF) has not been established. The purpose of this study was to examine the repeatability of submaximal endurance testing in stable CF. Fifteen adults with CF underwent two submaximal endurance tests carried out over a 7-day period. A subset of six subjects returned 28 days later for a third submaximal endurance test. Workload was set at 80% of maximum workload and exercise was performed to exhaustion. Oxygen consumption, minute ventilation, tidal volume, carbon dioxide output, respiratory rate, heart rate, and oxygen saturation were measured at rest, at end exercise and at four matched times during the submaximal endurance tests (20, 40, 60, and 80% of exercise duration calculated from the first endurance test). Submaximal endurance test time was highly repeatable with no significant learning effect identified on multiple testing. Submaximal endurance exercise time demonstrated a variability of 5.7% which is consistent with high levels of repeatability. Metabolic, ventilatory and cardiac variables were all also highly reproducible between test days. Submaximal endurance testing is repeatable in stable CF, confirming that submaximal endurance tests are a reliable tool for assessment of therapeutic benefit in patients with CF.

Exercise Performance Improves in Patients With COPD due to Respiratory Muscle Endurance Training

BACKGROUND

Impaired exercise tolerance is frequently observed in patients with COPD. Respiratory muscle endurance training (RMET) by means of normocapnic hyperpnea can be used to improve respiratory muscle function and probably exercise capacity. RMET is not applied on a large scale because complicated equipment is needed to maintain carbon dioxide homeostasis during hyperpnea, which can also be done by enlarging the dead space of the ventilatory system by breathing through a tube. Therefore, tube breathing might be a new, inexpensive method for home-based RMET. The aim of this study was to assess whether home-based RMET by means of tube breathing improves endurance exercise performance in patients with COPD.

METHODS

We randomized 36 patients with moderate-to-severe COPD to RMET by paced tube breathing (n = 18) or sham training (control, n = 18). Both groups trained twice daily for 15 min, 7 days per week, for 5 weeks.

RESULTS

Patients receiving RMET showed significant improvements in endurance exercise capacity (constant-load exercise on cycle ergometry; 18 min vs 28 min, p < 0.001), in perception of dyspnea (Borg score; 8.4 vs 5.4, p < 0.001), and respiratory muscle endurance capacity (sustainable inspiratory pressure; 25 cm H(2)O vs 31 cm H(2)O, p = 0.005). Quality of life (chronic respiratory disease questionnaire) also improved (78.7 to 86.6, p = 0.001). The control group showed no significant changes.

CONCLUSION

Home-based RMET by means of tube breathing leads to a significant improvement of endurance exercise capacity, a reduction in perception of dyspnea, and an improvement in quality of life in patients with moderate-to-severe COPD.

Reliability of cardiorespiratory measurements with a new ergospirometer during intense treadmill exercise in Thoroughbred horses

This study investigated the reliability of measurements with a new equine ergospirometer (Quadflow). Heart rate and blood lactate responses during exercise in horses wearing the Quadflow and an open flow mask were also compared. The mean percentage error of the oxygen uptake measurements was 8.2% (range 2.1-12.5%). Percent error for peak expiratory flow rates ranged from 6.1% to 9.4 %, and for minute ventilation from 2.5% to 7.4%. The coefficients of variation of the means of four measurements in two horses exercising continuously at 9.0 m/s were <5% for variables related to pulmonary ventilation, and was 7.7% for oxygen uptake. The Quadflow mask resulted in small increases in blood lactate concentration and relative heart rate during submaximal exercise. It was concluded that between- and within-test reliability statistics for important measurements in equine clinical exercise testing were acceptable for routine use in a veterinary practice or research laboratory.

Constant-load cycle endurance performance: test-retest reliability and validity in patients with COPD

The purpose of this study was to evaluate the rest-retest reliability and validity of a constant-load endurance exercise test on a cycle ergometer with a workload of 75% of maximal work capacity (W(max)) in patients with moderate to severe chronic obstructive pulmonary disease (COPD). In 60 patients with COPD (FEV(1) 40 +/- 15% pred), exercise endurance time was measured with a constant-load endurance exercise tests at 75% of W(max), on two different occasions. In a subgroup of 20 patients, test-retest reliability of the measurement of end-exercise ventilatory and metabolic responses was assessed. Validity of the cycle endurance test was assessed comparing endurance time and total work performed during the cycle endurance test to peak oxygen uptake (VO(2peak)) and the 12-minute walking distance (12MWD). Test and retest assessments of cycle endurance time did not differ statistically significantly (P =.40). Highly significant intraclass correlation coefficients (ICC > or = 0.85; P <.001) were found between test and retest of assessment of endurance time as well as of end-exercise ventilatory and metabolic responses. In addition, statistically significant correlation coefficients were found between VO(2peak) and endurance time (r = 0.50; P =.001) and total work performed (r = 0.72; P <.001) during the constant-load cycle test. Significant correlation coefficients of the same magnitude were found between 12MWD and endurance time (r = 0.58; P =.001) and total work performed (r = 0.72; P <.001) during the constant-load cycle test. It is concluded that constant-load exercise testing on a cycle ergometer with a workload of 75% of maximal work capacity is a reliable and valid method to assess exercise endurance in patients with COPD.

Evaluating the reproducibility and validity of the Aerobic Adaptation Test

PURPOSE

To examine the reproducibility and validity of a new submaximal, ramped cycle ergometer testing methodology known as the Aerobic Adaptation Test (AAT), which attempts to detect changes in submaximal work capacity and minimize participant discomfort.

METHODS

36 sedentary men (mean age = 48.1 +/- 10.2 yr [SD]) and 22 sedentary women (mean age = 51.9 +/- 10.2 yr [SD]) participated in the study. To test reproducibility, participants were tested twice with an average of 20 d between tests (+/-15 d). To test validity, participants were tested before and after a 6-month physical activity intervention, and outcomes were compared with standard measures of fitness (exercise time and oxygen consumption at 70% max heart rate). The main outcome variable of the AAT was work output (W) over a period of 3 min after reaching 70% maximal heart rate.

RESULTS

The average work output at 70% HRmax was highly reproducible, with a test-retest reliability of rho = 0.85 (P < 0.001). Average work output at 70% HRmax significantly increased after 6 months of physical activity intervention (87.8 +/- 32.9 W vs 95.5 +/- 37.9 W, P = 0.002), and changes in average work output at 70% HRmax correlated with changes in exercise time to elicit 70% HRmax (r = 0.87, P < 0.001) as well as changes in VO2 at 70% HRmax (r = 0.75, P < 0.001). Thus, the AAT appears to be a valid measure of submaximal work capacity.

CONCLUSIONS

The AAT is a reproducible and valid measure of submaximal work capacity that can serve as an effective means to evaluate physical activity interventions.