Last Word on Point:Counterpoint: The major limitation to exercise performance in COPD is 1) inadequate energy supply to the respiratory and locomotor muscles, 2) lower limb muscle dysfunction, 3) dynamic hyperinflation

Aliverti, Andréa; Macklem, Peter T.

doi:10.1152/japplphysiol.90745.2008

Cited by 16 publications

(15 citation statements)

References 5 publications

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“…The occurrence of some factors, such as inflammatory stress, physical deconditioning, prolonged use of corticosteroids, and hypoxemia, contributes to altering muscle contractile activity, triggering a series of adaptations that involve muscle fiber changes. According to one group of authors, ( 18 ) the work of breathing in the group of COPD patients who recruit abdominal muscles is twice that in the group of COPD patients who do not do so, being associated with increased dyspnea and decreased exercise tolerance. This is a possible explanation for our results, since patients may have a predominance of glycolytic fibers, may not recruit abdominal muscles, or both.…”

Section: Discussionmentioning

confidence: 99%

“…A ocorrência de alguns fatores, tais como estresse inflamatório, descondicionamento físico, uso prolongado de corticosteroides e hipoxemia, contribui para a modificação da atividade contrátil do músculo, desencadeando uma série de adaptações que envolvem uma alteração das fibras musculares. Segundo um grupo de autores, ( 18 ) o trabalho respiratório é duas vezes maior no grupo de pacientes com DPOC que são recrutadores da musculatura abdominal do que no grupo com DPOC não recrutador, associado à maior dispneia e menor tolerância ao exercício. Essa é uma possível explicação para os nossos resultados, pois os pacientes podem possuir uma predominância de fibras glicolíticas e/ou serem do grupo não recrutador da musculatura abdominal.…”

Section: Discussionunclassified

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Oxygen desaturation during the six-minute walk test in COPD patients

Moreira¹,

Medeiros²,

Boeno³

et al. 2014

J. bras. pneumol.

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Objective: To evaluate the behavior of oxygen saturation curves throughout the six-minute walk test (6MWT) in patients with COPD. Methods: We included 85 patients, all of whom underwent spirometry and were classified as having moderate COPD (modCOPD, n = 30) or severe COPD (sevCOPD, n = 55). All of the patients performed a 6MWT, in a 27-m corridor with continuous SpO2 and HR monitoring by telemetry. We studied the SpO2 curves in order to determine the time to a 4% decrease in SpO2, the time to the minimum SpO2 (Tmin), and the post-6MWT time to return to the initial SpO2, the last designated recovery time (RT). For each of those curves, we calculated the slope. Results: The mean age in the modCOPD and sevCOPD groups was 66 ± 10 years and 62 ± 11 years, respectively. At baseline, SpO2 was > 94% in all of the patients; none received supplemental oxygen during the 6MWT; and none of the tests were interrupted. The six-minute walk distance did not differ significantly between the groups. The SpO2 values were lowest in the sevCOPD group. There was no difference between the groups regarding RT. In 71% and 63% of the sevCOPD and modCOPD group patients, respectively, a ≥ 4% decrease in SpO2 occurred within the first minute. We found that FEV1% correlated significantly with the ΔSpO2 (r = −0.398; p < 0.001), Tmin (r = −0.449; p < 0.001), and minimum SpO2 (r = 0.356; p < 0.005). Conclusions: In the sevCOPD group, in comparison with the modCOPD group, SpO2 was lower and the Tmin was greater, suggesting a worse prognosis in the former.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionunclassified

Oxygen desaturation during the six-minute walk test in COPD patients

Moreira¹,

Medeiros²,

Boeno³

et al. 2014

J. bras. pneumol.

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“…The complex nature of exercise intolerance in patients with COPD has recently been reviewed. [13][14][15][16][17][18] …”

Section: Brief Overview Of Copd and The Pathogenesis Of Exercise Intomentioning

confidence: 99%

Exercise and COPD: Therapeutic Responses, Disease-Related Outcomes, and Activity-Promotion Strategies

Maltais

2013

The Physician and Sportsmedicine

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Chronic obstructive pulmonary disease (COPD) reduces patients' exercise capacities and their abilities to perform daily physical activities, thereby increasing morbidity and mortality rates. The cycle of dyspnea, deconditioning, and declining physical activity not only accelerates the progression of COPD but also increases the risk for developing or aggravating metabolic and cardiovascular diseases. Cardiovascular and metabolic comorbidities also limit physical function, and their disabling effects in combination with COPD may be greater than the effects of each disease alone. The impact of COPD and its treatment on the ability to exercise, and the degree of physical activity in daily life, can be measured by field-based tests (eg, the 6-minute walk test or incremental and endurance shuttle-walk test), laboratory-based tests (eg, incremental or constant work-rate treadmill and cycle-ergometer tests), and physical activity assessments (eg, questionnaires and accelerometers). Walking tests increase oxygen consumption and desaturation in patients with COPD more than cycling tests with similar work-rate profiles and may more closely resemble patients' normal activities. Despite the questionable relevance of exercise testing to patients' daily functionality, exercise parameters remain important predictors of survival in patients with COPD. Treatment of COPD (pharmacotherapy, pulmonary rehabilitation, or both) can increase exercise capacity and physical activity in daily life, which potentially slows the decline of lung function, reduces the frequencies of exacerbations and hospitalizations, decreases mortality, slows the progression of comorbidities, improves health-related quality of life, and increases the activity reserve for routine function. This article examines the interactions of reduced physical activity and decreased exercise capacity with the progression of COPD, comorbidities, and mortality. The article also describes the available exercise tests for patients with COPD and reviews the evidence indicating that treating COPD improves exercise capacity. Notably, it appears that even mild COPD reduces exercise capacity and daily physical activity, indicating the need for early intervention.

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“…Ventilatory components (expiratory flow limitation, dynamic hyperinflation, respiratory muscle dysfunction), gas exchange (hypoxemia, hypercapnia) as well as peripheral factors (locomotor muscle dysfunction, deconditioning) increase energy demands and decrease energy supplies, consequently leading to dyspnea and exercise limitation [28]. In COPD-associated PH hemodynamics and cardiac output are further elements of poor exercise tolerance.…”

Section: Discussionmentioning

confidence: 99%

Acute Effects of Aerosolized Iloprost in COPD Related Pulmonary Hypertension - A Randomized Controlled Crossover Trial

et al. 2012

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BackgroundInhaled iloprost potentially improves hemodynamics and gas exchange in patients with chronic obstructive pulmonary disease (COPD) and secondary pulmonary hypertension (PH).ObjectivesTo evaluate acute effects of aerosolized iloprost in patients with COPD-associated PH.MethodsA randomized, double blind, crossover study was conducted in 16 COPD patients with invasively confirmed PH in a single tertiary care center. Each patient received a single dose of 10 µg iloprost (low dose), 20 µg iloprost (high dose) and placebo during distinct study-visits. The primary end-point of the study was exercise capacity as assessed by the six minute walking distance.ResultsBoth iloprost doses failed to improve six-minute walking distance (p = 0.36). Low dose iloprost (estimated difference of the means −1.0%, p = 0.035) as well as high dose iloprost (−2.2%, p<0.001) significantly impaired oxygenation at rest. Peak oxygen consumption and carbon dioxide production differed significantly over the three study days (p = 0.002 and p = 0.003, accordingly). As compared to placebo, low dose iloprost was associated with reduced peak oxygen consumption (−76 ml/min, p = 0.002), elevated partial pressure of carbon dioxide (0.27 kPa, p = 0.040) and impaired ventilation during exercise (−3.0l/min, p<0.001).ConclusionsImprovement of the exercise capacity after iloprost inhalation in patients with COPD-associated mild to moderate PH is very unlikely.Trial RegistrationControlled-Trials.com ISRCTN61661881

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Last Word on Point:Counterpoint: The major limitation to exercise performance in COPD is 1) inadequate energy supply to the respiratory and locomotor muscles, 2) lower limb muscle dysfunction, 3) dynamic hyperinflation

Cited by 16 publications

References 5 publications

Oxygen desaturation during the six-minute walk test in COPD patients

Oxygen desaturation during the six-minute walk test in COPD patients

Exercise and COPD: Therapeutic Responses, Disease-Related Outcomes, and Activity-Promotion Strategies

Acute Effects of Aerosolized Iloprost in COPD Related Pulmonary Hypertension - A Randomized Controlled Crossover Trial

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