Evidence of pulmonary oedema triggered by exercise in healthy humans and detected with various imaging techniques.

This review summarizes current literature on pulmonary oedema triggered by above-ground exercise in healthy humans from studies that use various imaging techniques to detect oedema. Eleven studies were identified, comprising of 137 subjects (mean age = 28 years). Eighty per cent (n = 110) were males, and 20% (n = 27) were female. The studies were grouped into three different categories according to the severity of the exercise protocol, which were either prolonged, submaximal exercise of 15-min to 2 h in duration at approx. 50-75%VO(2max) and not to exhaustion (PROLONGED, n = 44), a VO(2max) test lasting 16-20 min in which the intensity of exercise was only maximum for about 2 min at the end of the test (GXT, n = 15), and maximum or near maximum effort exercise protocols at or near volitional exhaustion where the goal was to finish in the fastest possible time or maintain the highest possible workload (MAX EFFORT, n = 78). Only 16% of the subjects showed signs of oedema from PROLONGED exercise and no subjects (0%) showed signs of oedema from GXT exercise. Surprisingly, approx. 65% of the subjects showed signs of oedema triggered by MAX EFFORT exercise (chi(2) test of association; P < or = 0.01), which was independent of both sex, the level of hypoxia (inspired PO(2) = 106-118 mmHg vs. 149 mmHg), the timing of the post-exercise imaging (<10, >30 but <60 min, or >60 min) and VO(2max) (approx. 3.0 vs. approx. 4.8 L min(-1)). The data suggests that the chances of triggering pulmonary oedema from exhaustive MAX EFFORT exercise is 4x more compared with PROLONGED exercise. As well, the likelihood of triggering pulmonary oedema may be independent of lung size, sex, moderate levels of hypoxia, and aerobic fitness.