About the Authors

Stephan Lang

Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Validation, Visualization, Writing – original draft

Affiliation Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Robert Herold

Roles Formal analysis, Software, Visualization, Writing – review & editing

Affiliation Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Alexander Kraft

Roles Investigation, Writing – review & editing

Affiliation Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Volker Harth

Roles Resources, Writing – review & editing

Affiliation Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Alexandra M. Preisser

Roles Conceptualization, Data curation, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – review & editing

a.preisser@uke.de

Affiliation Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Competing Interests

SL carried out this study. At the time of the study 2016/17, in addition to his Ph.D. student position at the University Medical Center Hamburg-Eppendorf, SL worked as a Product Manager for CareFusion, Höchberg, Germany. This company provided the spiroergometry devices, the used material, and a small compensation for each of the 10 participants of the study. (CareFusion changed to Vyaire medical and is since 2015 part of BD an international medical technology company.) CareFusion as owner of the used CPET-device “Vyntus CPX” did not have any influence on the content and realisation of this study. CareFusion wanted to support SL with his doctoral thesis by providing the CPET-device without direct commercial purpose. This does not alter our adherence to PLOS ONE policies on sharing data and materials. SL does not have any patents on the used technology. RH, AK, VH and AMP declare, to have no conflicts of interest regarding this study.