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Titolo:
EFFECT OF DYNAMIC EXERCISE ON HUMAN CAROTID-CARDIAC BAROREFLEX LATENCY
Autore:
POTTS JT; RAVEN PB;
Indirizzi:
UNIV N TEXAS,HLTH SCI CTR,DEPT PHYSIOL,3500 CAMP BOWIE BLVD FT WORTH TX 76107 UNIV N TEXAS,HLTH SCI CTR,DEPT PHYSIOL FT WORTH TX 76107
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 3, volume: 37, anno: 1995,
pagine: 1208 - 1214
SICI:
0363-6135(1995)37:3<1208:EODEOH>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
SINUS BARORECEPTOR REFLEX; HEART-RATE; RESPONSES; RESPONSIVENESS; MECHANISMS; PRESSURE; DEVICE; VAGAL;
Keywords:
CAROTID SINUS BARORECEPTORS; NEURAL EFFECTOR TIME; CARDIAC VAGAL TONE; HUMANS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
J.T. Potts e P.B. Raven, "EFFECT OF DYNAMIC EXERCISE ON HUMAN CAROTID-CARDIAC BAROREFLEX LATENCY", American journal of physiology. Heart and circulatory physiology, 37(3), 1995, pp. 1208-1214

Abstract

We compared the beat-to-beat responses of heart rate (HR) after briefactivation of carotid baroreceptors in resting humans with the responses obtained during mild-to-moderate levels of dynamic exercise [25 and 50% of peak O-2 uptake (VO2peak)] to investigate the effect of exercise on baroreflex latency. Carotid baroreceptors were activated by a pressure pulse (5 s) of neck suction (NS, -80 Torr) and neck pressure (NP, +40 Torr) during held expiration. At rest the peak change in HR toNS/NP occurred during the first several heartbeats (1st-3rd beat), whereas during mild and moderate exercise peak HR responses occurred near the end of the NS/NP pulse (6th-8th beat). In contrast, time (s) to the peak change in HR was not different between rest and exercise (P >0.05). Reflex tachycardia to NP progressively decreased during exercise (17 +/- 3, 10 +/- 1, and 4 +/- 1% of control, rest vs. 25% VO2peak,VS 50% VO2peak, respectively, P < 0.05), and a strong positive correlation was found between the magnitude of the reflex tachycardia and a measure of HR variability (cardiac vagal tone index, r = 0.74, P < 0.0001). Reflex bradycardia to NS gradually increased during exercise (13+/- 2, 17 +/- 2, and 18 +/- 2% of control, rest vs. 25% VO2peak, VS 50% VO2peak respectively, P = 0.10) and was negatively correlated with cardiac vagal tone (r = 0.42, P < 0.06). These results suggested that 1) mild-to-moderate levels of dynamic leg exercise failed to alter carotid baroreflex latency and 2) the magnitude of carotid baroreflex tachycardia and bradycardia may depend on the functional level of cardiacvagal tone. Additionally, these findings suggest important implications regarding the use of pulse-synchronous changes in neck chamber pressure to assess maximal baroreflex sensitivity during exercise.

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Documento generato il 11/07/20 alle ore 07:52:07