Open AccessAltered chemosensitivity to CO 2 during exercise
Author(s) -
Yamashiro Stanley M.,
Kato Takahide,
Matsumoto Takaaki
Publication year - 2021
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.14882
Subject(s) - hypercapnia , ventilation (architecture) , peripheral chemoreceptors , medicine , central chemoreceptors , stimulation , peripheral , respiratory minute volume , anesthesia , chemoreceptor , inhalation , respiratory system , cardiology , carotid body , mechanical engineering , receptor , engineering
The effect of exercise on chemosensitivity to carbon dioxide (CO 2 ) has been controversial. Most studies have been based on rebreathing to alter inspired CO 2 which is poorly tolerated in exercise. Instead, inhaling a fixed 3% CO 2 from rest to moderate exercise was found to be well tolerated by seven normal subjects enabling CO 2 chemosensitivity to be studied with minimal negative reaction. Results showed that chemosensitivity to CO 2 following 5–6 min of stimulation was significantly enhanced during mild exercise ( p < 0.01). This motivated exploring how much of the dynamic ventilatory response to mild exercise breathing air could be predicted by a model with central and peripheral chemosensitivity. Chemoreceptor stimulation combined with hypercapnia has been associated with long‐term facilitation of ventilation (LTF). 3% CO 2 inhalation during moderate exercise led to ventilation augmentation consistent with LTF following 6 min of exercise in seven normal human subjects ( p < 0.01). Increased ventilation could not be attributed to hypercapnia or metabolic changes. Moderate exercise breathing air resulted in significantly less augmentation. In conclusion, both peripheral and central chemosensitivity to CO 2 increased in exercise with the peripheral chemoreceptors playing a dominant role. This separation of central and peripheral contributions was not previously reported. This chemoreceptor stimulation can lead to augmented ventilation consistent with LTF.