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, between6,7 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.
Margulis G, Katz A. Research Considerations in the Measurement of Relative Exercise Performance. Arch Intern Med. 1985;145(11):2131-2132. doi:10.1001/archinte.1985.00360110207052