1. The influence of central inspiratory drive on heart rate variability was investigated in young human subjects using power spectral analysis of R-R intervals. 2. The area of the high-frequency component occurring at the respiratory frequency (0.2-0.25 Hz) in the power spectral density curves was used as an index of respiratory sinus arrhythmia. 3. Central inspiratory drive was increased by breathing a CO2-enriched (5%) gas mixture and this condition was compared with a similar degree of ventilation produced voluntarily. 4. Tests were conducted on eight young subjects with and without low-dose scopolamine (scopoderm TTS) in a double-blind cross-over trial. 5. Scopolamine decreased heart rate and increased the high-frequency peak, suggesting that its main action on the cardiac vagal pathway was a peripheral one, possibly increasing the efficacy of vagal impulses on the cardiac pacemaker. 6. With scopolamine, CO2 breathing increased the area of the high-frequency component significantly more than a similar degree of ventilatory movements produced by voluntary hyperventilation. 7. It is concluded that respiratory sinus arrhythmia in humans is at least partly dependent on a central respiratory-cardiac coupling, most probably similar to that shown in animal studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.