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Titolo:
INFLUENCE OF APNEA ON CARDIOVASCULAR-RESPONSES TO NECK SUCTION DURINGEXERCISE
Autore:
SUNDBLAD P; LINNARSSON D;
Indirizzi:
KAROLINSKA INST,DEPT PHYSIOL & PHARMACOL,ENVIRONM PHYSIOL LAB S-17177STOCKHOLM SWEDEN
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 4, volume: 40, anno: 1996,
pagine: 1370 - 1374
SICI:
0363-6135(1996)40:4<1370:IOAOCT>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
SYMPATHETIC-NERVE ACTIVITY; BAROREFLEX RESPONSIVENESS; CHEMORECEPTOR REFLEX; CAROTID BAROREFLEX; VOLUNTARY APNEA; NORMAL HUMANS; BARORECEPTOR; PRESSURE; REST; VENTILATION;
Keywords:
CAROTID STIMULATION; BREATH HOLDING; ISOMETRIC EXERCISE; DYNAMIC EXERCISE; HEART RATE; BLOOD PRESSURE; BAROREFLEXES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
29
Recensione:
Indirizzi per estratti:
Citazione:
P. Sundblad e D. Linnarsson, "INFLUENCE OF APNEA ON CARDIOVASCULAR-RESPONSES TO NECK SUCTION DURINGEXERCISE", American journal of physiology. Heart and circulatory physiology, 40(4), 1996, pp. 1370-1374

Abstract

Short-lasting neck suction (NS) is a common method to assess the carotid-cardiac baroreflex, and NS is usually applied during apnea to avoid breath-synchronous variations of heart rate (HR) and blood pressure. We hypothesized that the apnea might provoke cardiovascular effects that could confound the HR and blood pressure responses to NS. HR and blood pressure responses to 10-s trains of 60-mmHg pulses of NS were studied in six male subjects during supine rest, upright rest, isometricarm exercise at 30% of maximal voluntary contraction, and dynamic legexercise at 100 W in the sitting position. Repeated NS sequences wereperformed during apnea preceded by a relaxed expiration to functionalresidual capacity and during eupnea. Initial HR responses to NS were similar during eupnea and apnea in all conditions. However, during isometric and dynamic exercise, recordings made under eupneic and apneic conditions differed during the second half of the NS period. During apneic isometric arm contraction, the elevation of mean carotid distending pressure (MCDP) (arterial pressure at carotid level minus NS pressure) was maintained at a 25-35% higher level than during eupneic isometric exercise over the last half of the NS period. In dynamic exercise,mean arterial pressure and MCDP started to increase after 3-5 s of apneic NS, whereas they were maintained during eupnea. One to three seconds later, HR started to drop markedly in apneic subjects, reaching values 20 beats/min lower than those in eupneic subjects at the end of the NS. We conclude that cardiovascular effects of apnea may appear after only 8 s of apnea in dynamic exercise and therefore could confound responses to NS.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 02:07:14