Training intensity at maximal fat oxidation differs among individuals. The aim of this study was to investigate whether a training recommendation according to a person's maximal fat oxidation rate [fat( (max)]) can be based on a lactate treadmill test and its resulting lactate concentration and heart rate profiles.Nine women and eleven men aged 31 - 49 years performed an ergospirometric and a standard lactate treadmill test. In the first test fat( (max)) was assessed by accustoming for 30 min at very low speed and then pace rising by three-minute stages. The standard lactate treadmill test was passed one to three weeks afterwards with stage increases every 5 min.When fat( (max)) was reached the probands had a median heart rate of 138 bpm. There was a significant difference (p < 0,001) from the heart rate at a lactate concentration of 2 mmol/l in the second test (median 153 bpm), serving as a reference for training recommendation. However, the median heart rate at fat( (max)) did not differ significantly from the value at first lactate rise (median 134 bpm). The heart rate interval at fat oxidation of more than 90 % of fat( (max)) ranged from a median of 125 to 151 bpm.A suitable approximation of a heart rate near fat( (max),) as a surrogate for the lactate test, seems to be the heart rate at first lactate rise or the heart rate corresponding to a lactate level of 2 mmol/l minus 15 bpm.