@article{Marín-Galindo2026, 
author = {Alberto Marín-Galindo and Edgardo Opazo-Diaz and Miguel Ramirez-Jimenez and Adrián Montes-de-Oca-García and Juan Corral-Pérez and Alejandro Perez-Bey and Cristina Casals and Jesus G. Ponce-Gonzalez},
title = {Validity and reliability of                      V            ˙                          O                    2      max       determination immediately after a maximal fat oxidation assessment in pre-diabetes/type 2 Diabetes Mellitus population},
year = {2026},
journal = {Sports Medicine and Health Science},
volume = {8},
number = {3},
pages = {327-334},
keywords = {Validation, Cardiorespiratory fitness, FatMax, Metabolic flexibility, Exercise tests, Exercise physiology},
url = {https://www.sciopen.com/article/10.1016/j.smhs.2025.02.004},
doi = {10.1016/j.smhs.2025.02.004},
abstract = {BackgroundMeasuring maximal fat oxidation (MFO) and maximal oxygen consumption    (                    V            ˙                          O                    2      max        ) typically requires two separate days, which can be time-consuming. This study aimed to assess the validity and reliability of a single-day test for measuring MFO and                      V            ˙                          O                    2      max       in individuals with pre-diabetes/type 2 diabetes (T2DM).MethodsTwenty adults with pre-diabetes/T2DM (10 women; [53.1 ​± ​8.8] years) participated in this cross-sectional study. Participants underwent a single-day MFO-                      V            ˙                          O                    2      max       protocol, followed by the traditional                      V            ˙                          O                    2      max       test on a cycle ergometer 4–7 days later, with both assessments performed using indirect calorimetry. The single-day test commenced with the MFO test, involving 15 ​W per 3 ​min increments until the respiratory exchange rate reached 1.0. After a 5-minute (min) rest, the                      V            ˙                          O                    2      max       test was conducted, starting at the last load and increasing by 15 ​W·min-1 until voluntary exhaustion. The traditional                      V            ˙                          O                    2      max       test involved a 15 ​W·min-1n incremental protocol until voluntary exhaustion, followed by a verification test at 110% of the previous maximum load.ResultsNo significant differences were observed between              M      F      O      −                          V            ˙                          O                    2      max       and traditional                      V            ˙                          O                    2      max       protocol in                      V            ˙                          O                    2      max       values ([2099.4 ​± ​534.1] ml·min-1 vs. [2119.1 ​± ​548.3] ml·min-1, p ​= ​0.715) or heart rate ([163.2 ​± ​18.2] beat/min vs. [164.5 ​± ​16.1] beat/min, p ​= ​0.485). The              M      F      O      −                          V            ˙                          O                    2      max       protocol test demonstrated excellent reliability (intraclass correlation coefficient ​= ​0.957), limits of agreement ranging from 300.06 ​ml·min-1 to −306.77 ​ml·min-1, and the standard error of measurement was 181.67 ​ml·min-1.ConclusionsTherefore, the single-day test is a valid and reliable method for assessing both MFO and                      V            ˙                          O                    2      max       in men and women with pre-diabetes/T2DM. With a mean total duration of (34 ​± ​8) min, this test enhances clinical applicability by significantly reducing the time and cost associated with traditional assessments.}
}