TY - JOUR
T1 - The paradox of systemic vasodilatation and sympathetic nervous stimulation in space
AU - Norsk, Peter
AU - Christensen, Niels Juel
N1 - Keywords: Adaptation, Physiological; Bed Rest; Blood Pressure; Cardiac Output; Humans; Peptides; Space Flight; Sympathetic Nervous System; Vasodilation; Weightlessness
PY - 2009
Y1 - 2009
N2 - Cardiac output is increased by some 18% by weightlessness during the initial week of spaceflight compared to upright standing or sitting on the ground and more so during the initial days of flight than at the end. In addition, mean 24-h diastolic, but not systolic pressure, is significantly decreased by 5mmHg. This is in accordance with observations that very acute weightlessness during parabolic airplane flights and a week of weightlessness in space leads to a decrease in systemic vascular resistance. That the arterial resistance vessels are dilated in space is in contrast to the augmented sympathetic nervous activity and decreased urine production, which have consistently been observed in astronauts in space. These contrasting observations require further investigation.
AB - Cardiac output is increased by some 18% by weightlessness during the initial week of spaceflight compared to upright standing or sitting on the ground and more so during the initial days of flight than at the end. In addition, mean 24-h diastolic, but not systolic pressure, is significantly decreased by 5mmHg. This is in accordance with observations that very acute weightlessness during parabolic airplane flights and a week of weightlessness in space leads to a decrease in systemic vascular resistance. That the arterial resistance vessels are dilated in space is in contrast to the augmented sympathetic nervous activity and decreased urine production, which have consistently been observed in astronauts in space. These contrasting observations require further investigation.
U2 - 10.1016/j.resp.2009.07.020
DO - 10.1016/j.resp.2009.07.020
M3 - Journal article
C2 - 19651245
SN - 1569-9048
VL - 169 Suppl 1
SP - S26-9
JO - Respiratory Physiology & Neurobiology
JF - Respiratory Physiology & Neurobiology
ER -