-transparent.png){kind=logo}
Exposure to microgravity redistributes body fluids with important secondary effects on cardiovascular function. We tested the hypothesis that the fluid shifts also affect pulmonary gas exchange. Microgravity was simulated in six male volunteers by a 10-day period of bedrest at 6 degrees head-down tilt (HDT). Lower body negative pressure (LBNP) and intravenous saline loading superimposed acute changes in fluid distribution on the prolonged effects of HDT. HDT produced relative dehydration and hypovolemia with decreased pulmonary blood flow and diffusing capacity. Before bedrest, pulmonary blood flow decreased by 24% during LBNP and diffusing capacity by 7%, while functional residual capacity increased by 14% (p less than 0.05). Intravenous saline loading caused a 24% increase in pulmonary blood-flow (p less than 0.05). Functional residual capacity decreased by 10% and diffusing capacity by 6% (p less than 0.05). Lung tissue volume did not change significantly. Head-down tilt had only minor effects on the responses to LBNP and saline loading. We conclude that LBNP and intravenous saline loading produce major changes in pulmonary blood-flow and minor effects on pulmonary gas exchange, and that the response to acute changes in fluid distribution is not significantly altered during simulated microgravity.
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
July 1992,
Acta astronautica,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
January 2015,
Aerospace medicine and human performance,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
February 2017,
Physiological reports,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
November 2017,
Journal of applied physiology (Bethesda, Md. : 1985),
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
February 1990,
The Physiologist,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
July 2015,
Journal of applied physiology (Bethesda, Md. : 1985),
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
October 1995,
Aviation, space, and environmental medicine,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
April 1994,
Acta astronautica,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
January 1995,
Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology,
A Hillebrecht, and
H Schulz, and
M Meyer, and
F Baisch, and
L Beck, and
C G Blomqvist
August 2011,
European journal of clinical investigation,
