Reproducibility and consistency of the responses to supine bicycle ergometry; evaluation in conjunction with beta 1-adrenoceptor occupancies.

A protocol is presented for supine bicycle ergometry in healthy subjects, which aims for a target increase of heart rate (HR = 140 beats min-1) after 4 min cycling under constant load. The required load is selected from a pre-study ergometry with stepwise increasing load. Repeated testing with this protocol was shown to yield highly reproducible ergometric HR-responses. Because of their high reliability, the ergometric endpoints and increments permit a highly sensitive comparison of beta 1-adrenoceptor antagonism across dose and time within a given compound. The relationship between the changes of the ergometric rise of HR and the beta 1-adrenoceptor occupancy (estimated from radioreceptor assay data) permits to evaluate the ergometric efficiency of different beta-adrenoceptor antagonists across time and doses and to identify eventual differences that do not relate primarily to the extent of beta 1-adrenoceptor antagonism itself.