biostudies-literatureUnknown11(24)Wadey CABackground Peak oxygen consumption (peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$) is traditionally divided ("ratio-scaled") by body mass (BM) for clinical interpretation. Yet, it is unknown whether ratio-scaling to BM can produce a valid size-independent expression of peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ in people with a Fontan circulation. Furthermore, people with a Fontan circulation have deficits in lean mass, and it is unexplored whether using different measures of body composition may improve scaling validity. The objective was to assess the validity of different scaling denominators (BM, stature, body surface area, fat-free mass, lean mass, and appendicular lean mass using ratio and allometric scaling). Methods and Results Eighty-nine participants (age: 23.3±6.7 years; 53% Journal of the American Heart Associatione026181https://www.ebi.ac.uk/biostudies/studies/S-EPMC9798799biostudies-literatureScaling Peak Oxygen Consumption for Body Size and Composition in People With a Fontan Circulation.PMC9798799Tran DLStuart GCordina RWilliams CALaohachai KBarker ARAyer JWadey CAfalseScaling Peak Oxygen Consumption for Body Size and Composition in People With a Fontan Circulation.Background Peak oxygen consumption (peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$) is traditionally divided ("ratio-scaled") by body mass (BM) for clinical interpretation. Yet, it is unknown whether ratio-scaling to BM can produce a valid size-independent expression of peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ in people with a Fontan circulation. Furthermore, people with a Fontan circulation have deficits in lean mass, and it is unexplored whether using different measures of body composition may improve scaling validity. The objective was to assess the validity of different scaling denominators (BM, stature, body surface area, fat-free mass, lean mass, and appendicular lean mass using ratio and allometric scaling). Methods and Results Eighty-nine participants (age: 23.3±6.7 years; 53% 2022-01-01T00:00:00Z2022 Dec2025-04-04T21:04:23.626Z2025-04-04T21:04:23.626ZS-EPMC97987993651523210.1161/JAHA.122.026181