Abstract: A method and apparatus for adjusting an implantable heart stimulator (1) in dependence on the effort exerted by the patient wearing the stimulator, using an external control programmer (2) associated in operation with the stimulator (1), a number of typical operating programs p.sub.i of the stimulator (1) being previously defined, each corresponding to a type of effort by the patient and characterized by specific values v of at least one operating parameter p of the stimulator (1), and the stimulator (1) is externally actuated, via the control programmer (2), so as to select the desired operating program p.sub.i, the result of the selection being that the stimulator (1) then operates in accordance with the selected operating program, so that the patient can automatically choose an operating program p.sub.i for the stimulator (1) in dependence on an effort to be made. The typical operating programs p.sub.i and consequently the specific values V of the parameters p, i.e.