title: Carotid baroreflex function at the onset of cycling in men.
abstract: Arterial baroreflex function is important for blood pressure control during exercise, but its contribution to cardiovascular adjustments at the onset of cycling exercise remains unclear. Fifteen healthy male subjects (24 ± 1 yr) performed 45-s trials of low- and moderate-intensity cycling, with carotid baroreceptor stimulation by neck suction at -60 Torr applied 0-5, 10-15, and 30-35 s after the onset of exercise. Cardiovascular responses to neck suction during cycling were compared with those obtained at rest. An attenuated reflex decrease in heart rate following neck suction was detected during moderate-intensity exercise, compared with the response at rest (P < 0.05). Furthermore, compared with the reflex decrease in blood pressure elicited at rest, neck suction elicited an augmented decrease in blood pressure at 0-5 and 10-15 s during low-intensity exercise and in all periods during moderate-intensity exercise (P < 0.05). The reflex depressor response at the onset of cycling was primarily mediated by an increase in the total vascular conductance. These findings evidence altered carotid baroreflex function during the first 35 s of cycling compared with rest, with attenuated bradycardic response, and augmented depressor response to carotid baroreceptor stimulation.
authors: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Brazil.|The Copenhagen Muscle Research Centre, Department of Anesthesia, University of Copenhagen, Copenhagen, Denmark.
authors: Thales C
authors: TC
authors: Barbosa
authors: Faculty of Physical Education, University of Brasilia, Brasilia, Brazil; lcvianna@unb.br.
authors: Lauro C
authors: LC
authors: Vianna
authors: Graduate School of Sport and Health Science, Ritsumeikan University, Kyoto, Japan.
authors: Takeshi
authors: T
authors: Hashimoto
authors: The Copenhagen Muscle Research Centre, Department of Anesthesia, University of Copenhagen, Copenhagen, Denmark.
authors: Lonnie G
authors: LG
authors: Petersen
authors: The Copenhagen Muscle Research Centre, Department of Anesthesia, University of Copenhagen, Copenhagen, Denmark.|Department of Neuroscience and Pharmacology, University of Copenhagen; and.
authors: Niels D
authors: ND
authors: Olesen
authors: Graduate School of Sport and Health Science, Ritsumeikan University, Kyoto, Japan.
authors: Hayato
authors: H
authors: Tsukamoto
authors: The Copenhagen Muscle Research Centre, Department of Anesthesia, University of Copenhagen, Copenhagen, Denmark.
authors: Henrik
authors: H
authors: Sørensen
authors: Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Japan.
authors: Shigehiko
authors: S
authors: Ogoh
authors: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Brazil.
authors: Antonio C L
authors: AC
authors: Nóbrega
authors: The Copenhagen Muscle Research Centre, Department of Anesthesia, University of Copenhagen, Copenhagen, Denmark.
authors: Niels H
authors: NH
authors: Secher
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D002346:Carotid Sinus / Q000294:innervation / Q000502:physiology*; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology*
keywords: arterial baroreflex; cycling onset; dynamic exercise; neck suction