It was hypothesized that the chronotropic response to intrathoracic pressure changes generated by cough may provide a reliable and rapid index of the cardioacceleratory capacity, a complex reflex response important for survival. In 27 adults in the supine position we measured the heart rate response following three forceful coughs performed over a 3-s period. At approximately four beats after the last cough, the mean instantaneous heart rate rose from 72 +/- 3 (SE) (range 54-91) to 94 +/- 5 beats/min (range 71-115), resulting in a maximal rate change of 31 +/- 3% (P less than 0.001). The time course and magnitude of response were reproducible within and similar among the subjects. Thus the heart rate response to large intrathoracic pressure transients generated by cough provides a quantitative and noninvasive estimate of integrity of the capacity for cardiac acceleration.