A method and wristop (wrist worn) device for monitoring physical exercise. The wristop device includes a central unit, in which there is a display face and to which a wristband is, or can be attached, sensor means for collecting a hemodynamic signal from the wrist, and a data-processing unit functionally connected to the sensor means, for deriving at least one physiological parameter from the hemodynamic signal. The data-processing unit of the wristop device is arranged to derive from the hemodynamic signal at least one physiological parameter depicting respiration, and further, on the basis of this, to calculate at least one training-effect parameter depending on the person and the exercise. In addition, the device makes it possible to eliminate the use of pulse bands in monitoring the training effect of exercise.
