Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 121-128 |
| Number of pages | 8 |
| Journal | Autonomic Neuroscience: Basic and Clinical |
| Volume | 110 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 27 2004 |
| Externally published | Yes |
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Keywords
- Arterial pressure variability
- Autonomic nervous system
- Baroreceptor reflex sensitivity
- Head-down bed rest
- Heart rate variability
ASJC Scopus subject areas
- Endocrine and Autonomic Systems
- Clinical Neurology
- Cellular and Molecular Neuroscience
Cite this
Autonomic cardiovascular changes during and after 14 days of head-down bed rest. / Hirayanagi, Kaname; Kamiya, Atsunori; Iwase, Satoshi; Mano, Tadaaki; Sasaki, Tsuyoshi; Oinuma, Miyuki; Yajima, Kazuyoshi.
In: Autonomic Neuroscience: Basic and Clinical, Vol. 110, No. 2, 27.02.2004, p. 121-128.Research output: Contribution to journal › Article
}
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
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
UR - http://www.scopus.com/inward/record.url?scp=1842471041&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=1842471041&partnerID=8YFLogxK
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 - Autonomic Neuroscience: Basic and Clinical
JF - Autonomic Neuroscience: Basic and Clinical
SN - 1566-0702
IS - 2
ER -