Maximal Fat Oxidation is Related to Performance in an Ironman Triathlon

Abstract The aim of the present study was to investigate the relationship between maximal fat oxidation rate (MFO) measured during a progressive exercise test on a cycle ergometer and ultra-endurance performance. 61 male ironman athletes (age: 35±1 yrs. [23–47 yrs.], with a BMI of 23.6±0.3 kg/m 2 [20.0–30.1 kg/m 2 ], a body fat percentage of 16.7±0.7% [8.4–30.7%] and a VO 2 peak of 58.7±0.7 ml/min/kg [43.9–72.5 ml/min/kg] SEM [Range]) were tested in the laboratory between 25 and 4 days prior to the ultra-endurance event, 2016 Ironman Copenhagen. Simple bivariate analyses revealed significant negative correlations between race time and MFO (r 2 =0.12, p