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.