Figure 4.
Average of estimated alveolar methane concentration and the inverse of the estimated ventilation-perfusion ratio during ergometer tests (n = 5) (a) as a function of time; (b) compared to each other; dotted and dashed lines indicate linear fit to data obtained under exercise (n = 64, R = 0.897, p = 0.018) and non-exercise conditions (n = 36, R = 0.787, p < 0.001), respectively. Line with a slope of unity is denoted by a grey straight line. The alveolar methane concentration, alveolar ventilation, and cardiac output were estimated as given in sections 2.4 and 2.5.