TY - JOUR
T1 - Autonomic cardiovascular changes during and after 14 days of head-down bed rest
AU - Hirayanagi, Kaname
AU - Kamiya, Atsunori
AU - Iwase, Satoshi
AU - Mano, Tadaaki
AU - Sasaki, Tsuyoshi
AU - Oinuma, Miyuki
AU - Yajima, Kazuyoshi
N1 - Funding Information:
We acknowledge the support of the Man–Vehicle Laboratory of the Massachusetts Institute of Technology, through the National Space Biomedical Research Institute (NASA grant NCC 9-58), in the preparation of the manuscript. We would like to express our appreciation to Dr. Y. Watanabe; the nurses and staff at Faculty of Health Science, Nagoya University; and the 12 subjects.
PY - 2004/2/27
Y1 - 2004/2/27
N2 - A 14-day, 6° head-down bed rest (HDBR) study was conducted with 12 healthy young men to determine whether there are transient responses of the cardiovascular autonomic regulatory system including cardiovascular, autonomic nervous, and cardiac baroreceptor reflex functions in the acute phases of HDBR and post-HDBR. Compared with the supine position before bed rest, the high-frequency band power (HFRRI) of RR intervals (RRIs) decreased significantly at 3, 6, and 24 h of HDBR. This tendency went on until 24 h post-HDBR. Three kinds of cardiac baroreceptor reflex sensitivity (BRS) were estimated from closed-loop approaches to simultaneously recorded spontaneous RRI and systolic arterial pressure (SAP) fluctuations. BRSsequence is based on the simultaneous changes between RRI and SAP. αLF and αHF are based on a cross-spectrum analysis for low- and high-frequency bands of RRI and SAP. Although BRSsequence decreased significantly at acute phases of both HDBR and post-HDBR, neither αLF nor αHF decreased significantly at any of the acute phases of HDBR and post-HDBR. Our results suggest that HF RRI and BRSsequence can be used effectively to reveal reductions in cardiac vagal nervous modulation on the sinus node and cardiac BRS within 24 h of both HDBR and post-HDBR.
AB - A 14-day, 6° head-down bed rest (HDBR) study was conducted with 12 healthy young men to determine whether there are transient responses of the cardiovascular autonomic regulatory system including cardiovascular, autonomic nervous, and cardiac baroreceptor reflex functions in the acute phases of HDBR and post-HDBR. Compared with the supine position before bed rest, the high-frequency band power (HFRRI) of RR intervals (RRIs) decreased significantly at 3, 6, and 24 h of HDBR. This tendency went on until 24 h post-HDBR. Three kinds of cardiac baroreceptor reflex sensitivity (BRS) were estimated from closed-loop approaches to simultaneously recorded spontaneous RRI and systolic arterial pressure (SAP) fluctuations. BRSsequence is based on the simultaneous changes between RRI and SAP. αLF and αHF are based on a cross-spectrum analysis for low- and high-frequency bands of RRI and SAP. Although BRSsequence decreased significantly at acute phases of both HDBR and post-HDBR, neither αLF nor αHF decreased significantly at any of the acute phases of HDBR and post-HDBR. Our results suggest that HF RRI and BRSsequence can be used effectively to reveal reductions in cardiac vagal nervous modulation on the sinus node and cardiac BRS within 24 h of both HDBR and post-HDBR.
KW - Arterial pressure variability
KW - Autonomic nervous system
KW - Baroreceptor reflex sensitivity
KW - Head-down bed rest
KW - Heart rate variability
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U2 - 10.1016/j.autneu.2004.01.001
DO - 10.1016/j.autneu.2004.01.001
M3 - Article
C2 - 15046736
AN - SCOPUS:1842471041
VL - 110
SP - 121
EP - 128
JO - Journal of the Autonomic Nervous System
JF - Journal of the Autonomic Nervous System
SN - 1566-0702
IS - 2
ER -