alexa Fluid shifts and muscle function in humans during acute simulated weightlessness.
Engineering

Engineering

Journal of Aeronautics & Aerospace Engineering

Author(s): Hargens AR, Tipton CM, Gollnick PD, Mubarak SJ, Tucker BJ,

Abstract Share this page

Abstract Head-down tilt is considered an effective experimental model to simulate weightlessness. To determine the acute effects of simulated weightlessness on transcapillary fluid balance, tissue fluid shifts, muscle function, and triceps surae reflex time, eight supine subjects were tilted 5 degrees head down for 8 h. A cephalic fluid shift from the legs was indicated by facial edema, nasal congestion, increased urine flow, decreased creatinine excretion, reduced calf girth, and decreased lower leg volume. As measured by wick catheters inserted under local anesthesia, interstitial fluid pressure in the tibialis anterior muscle (4.6 +/- 0.6 mmHg) and subcutaneous tissue (0.6 +/- 0.5 mmHg) of the lower leg fell significantly to -2.8 +/- 0.5 and -3.8 +/- 0.4 mmHg, respectively. Other transcapillary pressures (capillary and interstitial fluid colloid osmotic pressures) were relatively unchanged. Needle-biopsy specimens, obtained just before and after tilt, indicated that total water content of soleus muscle was unchanged during 8 h of head-down tilt. After head-down tilt, isometric strength and isokinetic strength of the plantar flexors were unchanged. Triceps surae reflex time associated with plantar flexion movement slowed slightly after the tilt maneuver. Collectively these results demonstrated a dehydration effect of head-down tilt on muscle and subcutaneous tissues of the lower leg that may affect muscle function.
This article was published in J Appl Physiol Respir Environ Exerc Physiol and referenced in Journal of Aeronautics & Aerospace Engineering

Relevant Expert PPTs

Relevant Topics

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords