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Titolo:
BLOOD-PRESSURE AND HEART-RATE RESPONSES TO SUDDEN CHANGES OF GRAVITY DURING EXERCISE
Autore:
LINNARSSON D; SUNDBERG CJ; TEDNER B; HARUNA Y; KAREMAKER JM; ANTONUTTO G; DIPRAMPERO PE;
Indirizzi:
KAROLINSKA INST,DEPT PHYSIOL & PHARMACOL,ENVIRONM PHYSIOL LAB S-17177STOCKHOLM SWEDEN UNIV TOKYO,DEPT HLTH ADM,BUNKYO KU TOKYO 113 JAPAN UNIV AMSTERDAM,DEPT PHYSIOL NL-1105 AZ AMSTERDAM NETHERLANDS UNIV UDINE,DEPT BIOMED SCI & TECHNOL I-33100 UDINE ITALY
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 6, volume: 39, anno: 1996,
pagine: 2132 - 2142
SICI:
0363-6135(1996)39:6<2132:BAHRTS>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTRAL VENOUS-PRESSURE; BARORECEPTOR STIMULATION; CAROTID BAROREFLEX; ARTERIAL; HUMANS; DEVICE;
Keywords:
CAROTID BARORECEPTORS; CARDIOPULMONARY BARORECEPTORS; DYNAMIC MODELING; MICROGRAVITY; PARABOLIC FLIGHT; TIME SHIFTS; VAGUS NERVE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
D. Linnarsson et al., "BLOOD-PRESSURE AND HEART-RATE RESPONSES TO SUDDEN CHANGES OF GRAVITY DURING EXERCISE", American journal of physiology. Heart and circulatory physiology, 39(6), 1996, pp. 2132-2142

Abstract

Heart rate (HR) and blood pressure responses to sudden changes of gravity during 80- to 100-W leg exercise were studied. One group was exposed to sudden changes between 1.0 and 0 g in the head-to-foot direction (G(z+)), starting upright and with repeated 30-s tilts to the supineposition. Another group was exposed to sudden G(z+) changes between 1.8 and 0 g in an aircraft performing parabolic flight. Arterial blood pressure at the level of the carotid (carotid distending pressure, CDP) showed a large transient increase by 27-47 mmHg when G(z+) was suddenly decreased and a similar drop when G(z+) was suddenly increased. HRdisplayed a reverse pattern with larger transients (-22 to -26 min(-1)) in response to G(z+) decreases and more sluggish changes of lower amplitude in the other direction. Central blood volume, as estimated from the inverse of transthoracic impedance (1/TTI), varied in concert with G(z+). A model is proposed in which HR responses are described as a function of CDP and 1/TTI after a time delay of 2.3-3.0 s and including a low-pass filter function with time-constants of 0.34-0.35 s for decreasing HR and time constants of 2.9-4.6 s for increasing HR. The sensitivity of the carotid component was around -0.8 to -1.0 min(-1). mmHg(-1) (4-7 ms/mmHg). The cardiopulmonary baroreceptor component was an additive input but was of modest relative importance during the initial HR responses. For steady-state HR responses, however, our model suggests that inputs from carotid and cardiopulmonary receptors are of equal importance.

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Documento generato il 14/07/20 alle ore 10:05:38