Method of measuring a cardiac pulsation during a sporting activity, mainly comprising the steps of: - transmitting light radiation into organic tissue, - detecting an optical signal derived from the interaction of said light radiation with the organic tissue, said optical signal including one component relating to the cardiac pulsation and one component relating to said movement carried out during said sporting activity, - detecting an acceleration signal containing an indication relating to said movement carried out during said sporting activity, - selecting the type of sporting activity being practised among a set of preselected activities, by means of a manual selector, and - calculating said cardiac pulsation from said optical signal and using said acceleration signal, by separating the components respectively relating to the cardiac pulsation and to the movement carried out, said cardiac pulsation calculation being adapted as a function of the type of sporting activity being practised, said calculation of the cardiac pulsation being based on an algorithm including a processing block for the pre-processing of the optical and acceleration signals, said pre-processing block comprising a step of filtering the optical signal using a filter whose width is adapted to the type of activity being practiced, the fact that for a given activity the heart rate is in a given range, being taken into account, said calculation of the cardiac pulsation being based on an algorithm including a processing block to separate components respectively relating to the cardiac pulsation and to the movement carried out, called the optical signal enhancement block, said optical signal enhancement block including: - a step of calculating the fundamental frequency of the movement, - a step of calculating the harmonics, and - a step of removing the movement frequencies thereby calculated by filtering of said optical signal using a comb type filter, said comb filter including pass-bands and rejection bands, the width of said bands (50, 52) being adapted to the type of activity being practised. - transmitting light radiation into organic tissue, - detecting an optical signal derived from the interaction of said light radiation with the organic tissue, said optical signal including one component relating to the cardiac pulsation and one component relating to said movement carried out during said sporting activity, - detecting an acceleration signal containing an indication relating to said movement carried out during said sporting activity, - selecting the type of sporting activity being practised among a set of preselected activities, by means of a manual selector, and - calculating said cardiac pulsation from said optical signal and using said acceleration signal, by separating the components respectively relating to the cardiac pulsation and to the movement carried out, said cardiac pulsation calculation being adapted as a function of the type of sporting activity being practised, said calculation of the cardiac pulsation being based on an algorithm including a processing block for the pre-processing of the optical and acceleration signals, said pre-processing block comprising a step of filtering the optical signal using a filter whose width is adapted to the type of activity being practiced, the fact that for a given activity the heart rate is in a given range, being taken into account, - a step of calculating the fundamental frequency of the movement, - a step of calculating the harmonics, and - a step of removing the movement frequencies thereby calculated by filtering of said optical signal using a comb type filter,