The cardiopulmonary response to maximal rowing exercise of short duration was studied in six healthy well-trained oarsmen. The lung diffusing capacity for carbon monoxide was significantly decreased below the pre-exercise value for 2.5 days post-exercise (P less than 0.05). Residual volume (RV) showed a significantly increased value at 30 min of recovery (P less than 0.01) with no change in total lung capacity. There was no significant change in transthoracic electrical impedance following exercise but a decrease may have been masked by the increased RV. The changes in the pulmonary parameters may reflect the occurrence of a transient interstitial lung oedema. Exercise-induced bronchoconstriction may be a part of the cardiopulmonary response as peak expiratory flow rate (PEFR) was significantly reduced at 30 min of recovery. The reason for the increase in pulmonary extravascular water volume may be a marked distension of the lung capillaries due to increased blood volume in the lungs and as a consequence increased vascular permeability. The changes may also be caused by impaired myocardial contractility indicated by a split impedance dZ/dt waveform, not previously described in healthy persons, which occurred in all six subjects immediately following exercise.