Factors influencing exercise performance in thoracic cancer

Our plain-English summary of Factors influencing exercise performance in thoracic cancer, by R. England, M. Maddocks, C. Manderson, et al (Respiratory Medicine, 2012).

The study

• Authors: R. England, M. Maddocks, C. Manderson, A. Wilcock
• Journal: Respiratory Medicine
• Published: 2012;106(2):294-9
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Patients with incurable thoracic cancer often complain of a reduced ability to exercise, but the cause of this has been little studied. Thus, we have explored how various physiological and psychological factors relate to exercise performance in this group.

Methods: Inspiratory muscle strength, peripheral muscle power, lung function and mastery over breathlessness were assessed using sniff nasal inspiratory pressure, leg extensor power, simple spirometry and the mastery domain of the Chronic Respiratory Disease Questionnaire respectively. Exercise performance was assessed using the Incremental Shuttle Walking Test (ISWT) during which patients wore a K4 b(2) system permitting measurement of resting and breakpoint heart rate, minute ventilation (VE) and oxygen uptake (VO(2)). Relationships between ISWT distance and the four factors were determined using correlation and β regression coefficients.

Results: Forty-one patients (21 male, mean (SD) age 64 (8) years) walked a median [IQR] of 320 [250-430] metres and reached a mean (SD) of 76 (10), 77 (25), and 48 (14) of their percent predicted maximum heart rate, VO(2), and VE respectively. Exercise performance was significantly associated only with inspiratory muscle strength (r = 0.42, P < 0.01) and peripheral muscle power (r = 0.39, P = 0.01). These factors were also significant determinants of exercise performance (β coefficients [95%CI] 1.77 [0.53, 3.01] and 1.22 [0.31, 2.14] respectively).

Conclusion: Of the factors examined, only inspiratory and peripheral muscle performance were significantly related to and predictive of exercise performance. Rehabilitation interventions which include inspiratory and peripheral muscle training are worth exploring further in this group of patients with thoracic cancer.

Copyright © 2011 Elsevier Ltd. All rights reserved.

In plain English

This study, from Nottingham in the UK, looked at what limits the ability to exercise in people with incurable cancer in the chest. Forty-one outpatients took part: 26 with non-small cell lung cancer, 11 with mesothelioma and four with small cell lung cancer. The authors measured breathing-muscle strength with a sniff test, leg muscle power, lung function with spirometry, and patients' sense of control over breathlessness with a questionnaire. They compared each measure with how far patients could walk on a test that got faster every minute. Patients walked a median of 320 metres. Distance was moderately and significantly linked with breathing-muscle strength (r = 0.42) and leg muscle power (r = 0.39), but not with lung function or the questionnaire score. Most patients (28) stopped because of breathlessness alone. Leaving out the mesothelioma patients made little difference to these links. The authors concluded that rehabilitation including breathing-muscle and leg-muscle training is worth exploring further. They noted that the group mixed different cancers, and that excluding patients with heart disease and other illnesses may limit how widely the findings apply.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional observational study comparing measured physical and psychological factors with performance on a walking test
• Who was studied: 41 outpatients with incurable thoracic cancer at Nottingham University Hospitals NHS Trust, UK (21 male, mean age 64), recruited from 79 eligible patients approached: 26 with non-small cell lung cancer, 11 with mesothelioma, 4 with small cell lung cancer. Study dates are not given.
• Exposure: Not a study of asbestos or any other environmental exposure. The factors examined were inspiratory (breathing) muscle strength, leg extensor (peripheral muscle) power, simple spirometry, and the mastery domain of the Chronic Respiratory Disease Questionnaire, each compared with Incremental Shuttle Walking Test distance.
• Main results:
  • The 41 patients walked a median distance of 320 metres (interquartile range 250 to 430) on the shuttle walking test.
  • Walking distance was moderately and significantly correlated with inspiratory muscle strength (r = 0.42, P = 0.01) and with peripheral muscle power (r = 0.39, P = 0.01), but not with spirometric values or mastery score.
  • In simple linear regression, only inspiratory muscle strength (coefficient 1.77, 95% CI 0.53 to 3.01) and peripheral muscle power (coefficient 1.22, 95% CI 0.31 to 2.14) were significant determinants of exercise performance.
  • Reasons for stopping the walk were breathlessness alone (28 patients), breathlessness and leg fatigue equally (9) and leg fatigue alone (3). One patient reported general fatigue.
  • Excluding the mesothelioma patients made little difference to the associations: inspiratory muscle strength r = 0.42, P = 0.01; peripheral muscle power r = 0.44, P = 0.01.
  • Lung cancer and mesothelioma patients showed no significant difference in any of the factors studied at baseline. The data were not shown.
• The authors' conclusion: The authors concluded that, of the factors examined, only inspiratory and peripheral muscle performance were significantly related to and predictive of exercise performance. They said that rehabilitation including inspiratory and peripheral muscle training is worth exploring further in this group.
• Limitations the authors state:
  • The group was heterogeneous: lung cancer and mesothelioma may affect the lung, chest wall or diaphragm differently.
  • Many patients were ineligible because of ischaemic heart disease and other illnesses, which may limit how widely the findings apply.
  • The data on numbers of patients excluded were incomplete.
  • Other factors that may predict exercise performance, such as left ventricular function, were not examined.
  • The sniff test can underestimate inspiratory muscle strength because it depends on patient effort.
  • Capillary blood gases tend to underestimate oxygen values, and difficulty obtaining samples left the blood gas data incomplete.
  • Some patients found the tight-fitting face mask of the gas analysis system uncomfortable.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Spirometry.

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