Craig A Williams1,2, Owen W Tomlinson1,2, Lucy V Chubbock1, Daniel Stevens3, Zoe L Saynor4, Patrick J Oades2, Alan R Barker1. 1. Children's Health and Exercise Research Center, Sport and Health Science, University of Exeter, Exeter, United Kingdom. 2. Pediatric Department, Royal Devon and Exeter NHS Foundation Trust Hospital, Exeter, United Kingdom. 3. Department of Pediatrics, Division of Respirology, Faculty of Medicine and School of Health and Human Performance, Faculty of Health Professions, Dalhousie University, Halifax, Canada. 4. Department of Sport and Exercise Science, Faculty of Science, University of Portsmouth, Portsmouth, United Kingdom.
Abstract
BACKGROUND: Maximal cardiopulmonary exercise testing is recommended on an annual basis for children with cystic fibrosis (CF), due to clinically useful prognostic information provided by maximal oxygen uptake (V̇O2max ). However, not all patients are able, or willing, to reach V̇O2max , and therefore submaximal alternatives are required. This study explored the validity of the oxygen uptake efficiency slope (OUES) as a submaximal measure of V̇O2max in children and adolescents with CF. METHODS: Data were collated from 72 cardiopulmonary exercise tests (36 CF, 36 controls), with OUES determined relative to maximal and submaximal parameters of exercise intensity, time, and individual metabolic thresholds. Pearson's correlation coefficients, independent t-tests, and factorial ANOVAs were used to determine validity. RESULTS: Significant (P < 0.05) correlations with V̇O2max were observed for most expressions of OUES, but were consistently weaker in CF (r = 0.30-0.47) when compared to CON (r = 0.58-0.89). Mean differences for all OUES parameters between groups were not significant (P > 0.05). When split by V̇O2max tertiles, minimal significant differences were found between, and within, groups for OUES, indicating poor discrimination of V̇O2max . CONCLUSIONS: The OUES is not a valid (sub) maximal measure of V̇O2max in children and adolescents with mild-to-moderate CF. Clinicians should continue to use maximal markers (ie, V̇O2max ) of exercise capacity.
BACKGROUND: Maximal cardiopulmonary exercise testing is recommended on an annual basis for children with cystic fibrosis (CF), due to clinically useful prognostic information provided by maximal oxygen uptake (V̇O2max ). However, not all patients are able, or willing, to reach V̇O2max , and therefore submaximal alternatives are required. This study explored the validity of the oxygen uptake efficiency slope (OUES) as a submaximal measure of V̇O2max in children and adolescents with CF. METHODS: Data were collated from 72 cardiopulmonary exercise tests (36 CF, 36 controls), with OUES determined relative to maximal and submaximal parameters of exercise intensity, time, and individual metabolic thresholds. Pearson's correlation coefficients, independent t-tests, and factorial ANOVAs were used to determine validity. RESULTS: Significant (P < 0.05) correlations with V̇O2max were observed for most expressions of OUES, but were consistently weaker in CF (r = 0.30-0.47) when compared to CON (r = 0.58-0.89). Mean differences for all OUES parameters between groups were not significant (P > 0.05). When split by V̇O2max tertiles, minimal significant differences were found between, and within, groups for OUES, indicating poor discrimination of V̇O2max . CONCLUSIONS: The OUES is not a valid (sub) maximal measure of V̇O2max in children and adolescents with mild-to-moderate CF. Clinicians should continue to use maximal markers (ie, V̇O2max ) of exercise capacity.
Authors: Owen W Tomlinson; Alan R Barker; Lucy V Chubbock; Daniel Stevens; Zoe L Saynor; Patrick J Oades; Craig A Williams Journal: Eur J Appl Physiol Date: 2018-07-12 Impact factor: 3.078