Abstract

Pulmonary diffusing capacity (DIco), together with spirometric variables, arterial oxygen tension (paO2) and cardiac output were determined before and at intervals after maximal arm cranking, treadmill running and ergometer rowing. Independent of the type of exercise, DIco increased immediately post-exercise from a median 13.6 (range 7.3-16.3) to 15.1 (9.3-19.6) mmol/min/kPa (P<0.01). However, it decreased to 11.6 (6.9-15.5) mmol/min/kPa (P<0.01) after 24 h with cardiac output and paO2 at resting values, and DIco normalized after 20 h. Thoracic electrical impedance at 2.5 and 100 kHz increased slightly post-exercise, indicating a decrease in thoracic fluid balance, and there were no echocardiographic signs of left ventricular failure at the time of the decrease in DIco. Also, active muscle (limb) circumference and volume, and an increase in haematocrit from 43.8 (38.0-47.0) to 47.1 (42.7-49.8) (P<0.01), had normalized at the time of the decrease in DIco. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, peak and peak mid-expiratory flows did not change. However, total lung capacity increased from 6.8 (5.0-7.6) to 7.0 (5.1-7.8) litres (P<0.05) immediately after exercise and remained elevated at 6.9 (5.1-8.7) litres (P<0.05) when a decrease in DIco was noted. The results demonstrate that independent of the type of maximal exercise, an approximate 15 reduction in DIco takes place 2-3 h post-exercise, which normalizes during the following day of recovery. Verf.-Referat