Biomaterial Database

The effect of CO2 on ventilation and breath-holding during exercise and while breathing through an added resistance. 1969

T J Clark, and S Godfrey

1. Ventilation was measured while subjects were made to rebreathe from a bag containing CO(2) and O(2) in order to expose them to a steadily rising CO(2) tension (P(CO2)). The object of the experiments was to determine the effect of a variety of stimuli upon the increase in ventilation and fall in breath-holding time which occurs in response to the rising P(CO2).2. Steady-state exercise at 200 kg.m/min resulted in a small fall in the slope of the ventilation-CO(2) response curve (S(V)) and a small, though not statistically significant, fall in the P(CO2) at which ventilation would be zero by extrapolation (B(V)). There was a marked fall in the slope of the breath-holding-CO(2) response curve (S(BH)) and an increase in the P(CO2) at which breath-holding time became zero by extrapolation (B(BH)).3. These results have been interpreted with the aid of a model of the control of breath-holding and it is suggested that there is no change in CO(2) sensitivity on exercise, either during rebreathing or breath-holding.4. An increase in the resistance to breathing caused a marked reduction in S(V) and B(V), but no change in the breath-holding-CO(2) response curve. These findings suggest that the flattening of the ventilation-CO(2) response curve is mechanical in origin and acute airway obstruction produces no change in CO(2) sensitivity.5. On the basis of these results, we suggest that more information about CO(2) sensitivity can be obtained by a combination of ventilation and breath-holding-CO(2) response curves.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008962	Models, Theoretical	Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Experimental Model,Experimental Models,Mathematical Model,Model, Experimental,Models (Theoretical),Models, Experimental,Models, Theoretic,Theoretical Study,Mathematical Models,Model (Theoretical),Model, Mathematical,Model, Theoretical,Models, Mathematical,Studies, Theoretical,Study, Theoretical,Theoretical Model,Theoretical Models,Theoretical Studies
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D012129	Respiratory Function Tests	Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.	Lung Function Tests,Pulmonary Function Tests,Function Test, Pulmonary,Function Tests, Pulmonary,Pulmonary Function Test,Test, Pulmonary Function,Tests, Pulmonary Function,Function Test, Lung,Function Test, Respiratory,Function Tests, Lung,Function Tests, Respiratory,Lung Function Test,Respiratory Function Test,Test, Lung Function,Test, Respiratory Function,Tests, Lung Function,Tests, Respiratory Function
D001945	Breathing Exercises	Therapeutic exercises aimed to deepen inspiration or expiration or even to alter the rate and rhythm of respiration.	Respiratory Muscle Training,Exercise, Breathing,Muscle Training, Respiratory,Training, Respiratory Muscle
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D002628	Chemoreceptor Cells	Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.	Chemoreceptive Cells,Cell, Chemoreceptive,Cell, Chemoreceptor,Cells, Chemoreceptive,Cells, Chemoreceptor,Chemoreceptive Cell,Chemoreceptor Cell
D005082	Physical Exertion	Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.	Physical Effort,Effort, Physical,Efforts, Physical,Exertion, Physical,Exertions, Physical,Physical Efforts,Physical Exertions
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001049	Apnea	A transient absence of spontaneous respiration.	Apneas