Kampert et al. express questions regarding (1) the measurement of pulmonary function, (2) listing of the data, (3) and a model of blood flow redistribution at peak exercise described by Harms et al. In addition, (4) they comment on the peak metabolic demand of the three conditions.
Ad 1: During CPET, VE sm: −12.0 ± 12.6%, ffpm: −23.1 ± 13.6%, p = 0.001, tidal volume sm −9.9 ± 11.3% and ffpm: −14.4 ± 13.0%, p = 0.016, inhalation time sm: +12 ± 15%, ffpm: +19 ± 16%, p < 0.001, compared to nm.
Ad 2: The complete results are listed in Tables 2 and 3.
Ad 3: Harms et al. (1998) were cited describing possible changes in the distribution of total blood flow with additional work of breathing (e.g. higher breathing resistance) [1].
Ad 4: At maximum load, the metabolic demands were similar in all three conditions. The respiratory exchange ratio (RER) did not differ between the tests (nm 1.13 ± 0.08, sm 1.15 ± 0.09, ffpm 1.13 ± 0.08, one-way ANOVA p = 0.596).
A straightforward way to get a feeling for the clear results of the study could be to personally try out the effects of sm and ffpm during exercise.
Funding
Open Access funding enabled and organized by Projekt DEAL.
Footnotes
The original online version of this article was revised due to a retrospective Open Access order.
Change history
11/19/2021
A Correction to this paper has been published: 10.1007/s00392-021-01966-0
Reference
- 1.Harms CA, Wetter TJ, McClaran SR, Pegelow DF, Nickele GA, Nelson WB, Hanson P, Dempsey JA. Effects of respiratory muscle work on cardiac output and its distribution during maximal exercise. J Appl Physiol. 1998;85(2):609–618. doi: 10.1152/jappl.1998.85.2.609. [DOI] [PubMed] [Google Scholar]