A method of determining the ventilatory threshold of a subject in real time during an exercise session wherein data relating to physiological parameters of said subject are acquired and stored in function of time during the exercise session, said data including at least data indicative of the respiration and of the heart beat rate. The method includes a VT determination routine comprising the steps of: a) computing a first value of ventilatory threshold according to a first approach based on data relating to at least one of the physiological parameters acquired for the exercise session b) computing a second value of ventilatory threshold according to a different, second approach based on data relating to at least one of the physiological parameters acquired for the exercise session c) determining a confidence index for each of said first and second values of ventilatory threshold, wherein said confidence index reflects at least one of the detectability of the ventilatory threshold and the matching between the value of ventilatory threshold according to one approach and that according to the other approach.
