Carbon Dioxide Expiration and Performance Fatigability Following Aerobic Exercise Training: A Longitudinal, Observational, Pilot Study.

Twenty healthy adults only, so it cannot be applied directly to patients with lung disease, fatigue, or functional limits. The study was a single cohort pre-post pilot, not a randomised controlled trial, so improvement could be due to time, testing, or other factors. Excess carbon dioxide expiration was estimated, not directly measured, and the linear model assumptions may not account for individual variation. Health status was based on self-report and a readiness questionnaire, not objective medical screening in the supplied text. The sample was a non-randomised convenience sample recruited by advertisements, which limits generalisability. The supplied text says fatigability measures decreased significantly but does not provide the numerical values for that primary outcome. One participant dropped out after the first testing day, and one post-test endurance record was missing because of equipment malfunction. The paper reports associations between excess carbon dioxide expiration and fatigability, not proof that excess carbon dioxide causes fatigue.

All authors declared no conflicts of interest. The supplied text does not state a funding source.

Do not conclude that excess carbon dioxide expiration causes fatigue or that this training program will improve fatigue in patients. The study included 20 healthy adults, used estimated excess carbon dioxide, and reported associations after a four week program, not a controlled test in clinical populations.