The Journal of physiology
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The Journal of physiology · Feb 1975
Interrelationships of the volume and time components of individual breaths in resting man.
1. The volume and time components of individual breaths have been investigated under 'steady-state' conditions during air-breathing in fifteen subjects and, in a further six subjects, also during the addition of 1-5 and 3% CO2 to the inspired gas. 2. A computer-assisted method has been used to derive from the air flow record the individual breath values of tidal volume (VT), inspiratory duration (TI), expiratory duration (TE) and cycle duration (TC = TI + TE) for a sequence of breaths in the various steady-state conditions. 3. ⋯ It is concluded that the previously observed tendency for ventilation to be held constant from breath to breath during steady-state breathing depends predominantly on the tendency for VI to be held constant. Close restraints are evidently not imposed on the individual values of VT and TI under these conditions. The neural mechanism generating breathing appears to control ventilation principally by regulating the rate of inspiratory air flow and secondarily TE.