You are here

Article Text

Article menu

Download PDFPDF

XML
Original research
Cardiorespiratory fitness on a treadmill in an adult cystic fibrosis population
  1. Ole Torvanger1,2,3,
  2. Audun Os2,3,
  3. Ole Henning Skjonsberg1,2,
  4. Elisabeth Edvardsen2,4
  1. 1Faculty of Medicine, University of Oslo, Oslo, Norway
  2. 2Department of Pulmonary Medicine, Oslo University Hospital, Oslo, Norway
  3. 3Norwegian Resource Centre for Cystic Fibrosis, Oslo University Hospital, Oslo, Norway
  4. 4Sports Medicine, Norwegian School of Sport and Sciences, Oslo, Norway
  1. Correspondence to Dr Audun Os; auduos{at}ous-hf.no

Abstract

Objectives (1) To describe the cardiorespiratory fitness (CRF) in an adult cystic fibrosis population related to sex and age, (2) to evaluate the cause of low CRF and (3) to study the association between peak oxygen uptake (VO2peak) and forced expiratory volume in 1 s (FEV1).

Methods A total of 204 cardiopulmonary treadmill exercise tests (CPETs) performed by 116 patients were included. VO2peak, gas exchange, heart rate, oxygen saturation and ventilatory variables were measured.

A low CRF was defined as a VO2peak <80% of predicted, ventilatory limitation was defined as a breathing reserve <15%, exercise hypoxaemia was defined as an oxygen saturation <88% and ventilation-perfusion mismatch was defined as a minute ventilation/ventilatory equivalent for carbon dioxide slope ≥34. In patients who had performed three or more CPETs, the annual change in FEV1 and VO2peak were calculated using linear regression.

Results The VO2peak was 40.6±11.5 and 35.2±8.9 mL kg−1 min−1, which was 87±23 and 93±20 in percentage of predicted for men and women, respectively. VO2peak was moderately affected by age, for men (r=−0.36, p<0.001) and women (r=−0.53, p<0.001), respectively. In 45 of 101 tests where CRF was low, no cardiorespiratory limiting factors were identified. The correlation coefficient between VO2peak and FEV1 was r=0.64 (p<0.001). In participants with a low CRF, FEV1 ranged from 20% to 112% of predicted.

Conclusions The correlation between VO2peak and FEV1 was moderate. The majority of the tests resulted in a VO2peak within normal limits. Interestingly, 44% of the tests with a low VO2peak could be explained by deconditioning. Thus, exercise therapy may be beneficial for these patients.

  • exercise testing
  • pulmonary
  • respiratory
  • physiology
http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/bmjsem-2020-000765

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    View Full Text

    Footnotes

    • Contributors All authors have given substantial contributions to the submitted article and have approved the final version.

    • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

    • Competing interests None declared.

    • Patient consent for publication Not required.

    • Ethics approval The study is approved by the Oslo University Hospital’s Data and Privacy Protection Officer (approval 18/09502, database 2016/3030), provided that the anonymity of all individual test results is maintained.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data availability statement Data are available upon reasonable request. Derived data might be available from the corresponding author AO upon reasonable request and after evaluation by Oslo University Hospital’s Data and Privacy Protection Officer.