CO2 does not affect passive exercise ventilatory decline
| العنوان: | CO2 does not affect passive exercise ventilatory decline |
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| المؤلفون: | James Duffin, Harold J. Bell |
| المصدر: | Journal of Applied Physiology. 95:322-329 |
| بيانات النشر: | American Physiological Society, 2003. |
| سنة النشر: | 2003 |
| مصطلحات موضوعية: | Adult, Male, medicine.medical_specialty, Adolescent, Respiratory rate, Physiology, Rest, Hyperpnea, Physical exercise, pCO2, Physiology (medical), Internal medicine, Respiration, Tidal Volume, medicine, Humans, Respiratory system, Muscle, Skeletal, Exercise, Tidal volume, Leg, Electromyography, business.industry, Carbon Dioxide, medicine.disease, Respiratory Mechanics, Cardiology, Breathing, Physical therapy, Female, business |
| الوصف: | Breathing increases abruptly at the start of passive exercise, stimulated by afferent feedback from the moving limbs, and declines toward a steady-state hyperpnea as exercise continues. This decline has been attributed to decreased arterial CO2 levels and adaptation in afferent feedback; however, the relative importance of these two mechanisms is unknown. To address this issue, we compared ventilatory responses to 5 min of passive leg extension exercise performed on 10 awake human subjects (6 men and 4 women) in isocapnic and poikilocapnic conditions. Endtidal Pco2 decreased significantly during poikilocapnic (Δ = -1.5 ± 0.5 Torr, P < 0.001), but not isocapnic, passive exercise. Despite this difference, the ventilatory responses to passive exercise were not different between the two conditions. Using the fast changes in ventilation at the start (5.46 ± 0.40 l/min, P < 0.001) and end (3.72 ± 0.33 l/min, P < 0.001) of passive exercise as measures of the drive to breathe from afferent feedback, we found a decline of 68%. We conclude that the decline in ventilation during passive exercise is due to an adaptation in the afferent feedback from the moving limbs, not a decline in CO2 levels. |
| تدمد: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.01176.2002 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0ea5e4c54379435af5420c93be1851cf https://doi.org/10.1152/japplphysiol.01176.2002 |
| رقم الانضمام: | edsair.doi.dedup.....0ea5e4c54379435af5420c93be1851cf |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15221601 87507587 |
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| DOI: | 10.1152/japplphysiol.01176.2002 |