Cardiopulmonary exercise testing with supramaximal verification produces a safe and valid assessment of V̇O2max in people with cystic fibrosis

Adam John Causer, Janis K. Shute, Michael H. Cummings, Anthony Ian Shepherd, Victoria Bright, Gary Connett, Mark I. Allenby, Mary P. Carroll, Thomas Daniels, Zoe Louise Saynor

Research output: Contribution to journalArticlepeer-review


Introduction - The validity and safety of using supramaximal verification (Smax) to confirm a maximal effort during cardiopulmonary exercise testing (CPET) in people with cystic fibrosis (CF) and/or those with severe disease has been questioned. Therefore, this study aimed to investigate these concerns in children, adolescents and adults with mild-to-severe CF lung disease. 

Methods - Retrospective analysis of 17 pediatric and 28 adult participants with CF (age range: 9.2-62.9 y; forced expiratory volume in 1 s: 66.7% [range: 29.9-102.3%]; 30 males) who completed a routine ramp incremental cycling test to determine peak oxygen uptake (V̇O2peak). Maximal oxygen uptake (V̇O2max) was subsequently confirmed by Smax at 110% of peak power output. 

Results - All participants satisfied the criteria to verify a maximal effort during CPET. However, Smax-V̇O2peak exceeded ramp-V̇O2peak in 3/14 (21.4%) of pediatric and 6/28 (21.4%) adult exercise tests. A valid measurement of V̇O2max was attained in 85.7% of pediatric and 96.4% of adult exercise tests, as Smax-V̇O2peak did not exceed ramp-V̇O2peak by > 9%. Nine adults experienced a ≥ 5% reduction in arterial O2 saturation during CPET; 4 during both the ramp and Smax, 3 during only the ramp and 2 during Smax only. Smax did not significantly worsen perceived breathing effort, chest tightness, throat narrowing or exertion compared with ramp incremental testing. 

Conclusions - Given the clinical importance of aerobic fitness in people with CF, incorporating Smax is recommended to provide a safe and valid measure of V̇O2max in children, adolescents and adults who span the spectrum of CF disease severity.
Original languageEnglish
JournalJournal of Applied Physiology
Early online date2 Aug 2018
Publication statusEarly online - 2 Aug 2018


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