Research Considerations in the Measurement of Relative Exercise Performance

To the Editor.  —We read with interest the article by Bohlen et al¹ and we agree with them and with the concepts raised in the editorial by Stein² in the September 1984 Archives. However, we think that it is not possible to compare effort in the supine position with performance on a treadmill because of the differences in the hemodynamic response between the two positions.^3,4 Furthermore, the differences between⁵ trained healthy and untrained healthy subjects and, even more so, between^6,7 healthy subjects and patients with coronary heart disease or⁸ congestive heart failure must be considered.The prominent difference in the hemodynamic response in the supine and upright positions is well documented.