PMID- 9737753
OWN - NLM
STAT- MEDLINE
DCOM- 19981112
LR  - 20131121
IS  - 0095-6562 (Print)
IS  - 0095-6562 (Linking)
VI  - 69
IP  - 9
DP  - 1998 Sep
TI  - Plasma volume expansion with oral fluids in hypohydrated men at rest and during 
      exercise.
PG  - 837-44
AB  - BACKGROUND: The purpose for this study was to evaluate various carbohydrate 
      (CHO)-electrolyte fluid formulations for consumption by astronauts to maintain or 
      restore their plasma volume (PV) and total body water (TBW) during and after 
      extravehicular activity (exercise experiment, EE) and for a few hours before 
      reentry and immediately after landing (rest experiment RE). HYPOTHESIS: That 
      fluid formulation electrolyte content would be more important than osmotic (Osm) 
      content for increasing or maintaining PV during the RE and EE. METHODS: In the 
      RE, 5 healthy men (23-44 yr), previously dehydrated for 24 h, drank 6 fluid 
      formulations (Water, 19.6 Na, 157 Na, 19.6 Na + glucose, and the prepared drinks 
      Performances and Power)--one each at weekly intervals, and then sat for 70 min. 
      In the EE, four healthy 24-h dehydrated men (30-46 yr) exercised for 70 min 
      supine on a cycle ergometer (load = 71 +/- 1% peak VO2). RESULTS: Rest: Subjects 
      who consumed formulations with total Osm concentrations nearer the normal range 
      (157 Na - 270 mOsm x kg(-1), Performance with 19.6 mEq x L(-1) Na - 380 mOsm, and 
      to some extent Power with 23.5 mEq x L(-1) Na - 390 mOsm) had the greater 
      increases in PV; intake of drink 157 Na, with the largest Na content, induced the 
      greatest hypervolemia of 7.6% (p < 0.05). The various additional ions, in 
      addition to 19.6 Na, probably contributed to the 4.6% (p < 0.05) hypervolemia 
      with Performance. Water was not effective. Exercise: Stabilization of PV between 
      15-70 min was not related to drink total CHO, Na or Osm content. Performance and 
      157 Na were no more effective than 19.6 Na or 19.6 Na + glu for PV stabilization. 
      Water was the least effective. Regulatory mechanisms controlling PV during 
      exercise appear to be independent of oral fluid formulation Osm-electrolyte 
      content. CONCLUSIONS: Drink cation (sodium) content is more important that its 
      total osmotic content for increasing plasma volume at rest. Fluid formulations 
      with greater hypervolemic action in resting subjects may not be as effective 
      during exercise; therefore different formulations for use during exercise appear 
      to be necessary.
FAU - Greenleaf, J E
AU  - Greenleaf JE
AD  - Life Science Division, NASA, Ames Research Center, Moffett Field, CA 94035-1000, 
      USA.
FAU - Jackson, C G
AU  - Jackson CG
FAU - Geelen, G
AU  - Geelen G
FAU - Keil, L C
AU  - Keil LC
FAU - Hinghofer-Szalkay, H
AU  - Hinghofer-Szalkay H
FAU - Whittam, J H
AU  - Whittam JH
LA  - eng
PT  - Clinical Trial
PT  - Comparative Study
PT  - Journal Article
PT  - Randomized Controlled Trial
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Aviat Space Environ Med
JT  - Aviation, space, and environmental medicine
JID - 7501714
RN  - 0 (Rehydration Solutions)
RN  - 9NEZ333N27 (Sodium)
SB  - IM
MH  - Adult
MH  - Body Fluids/physiology
MH  - Chemistry, Pharmaceutical
MH  - Dehydration/metabolism/*physiopathology/*therapy
MH  - Exercise/*physiology
MH  - Exercise Test
MH  - Fluid Therapy/*methods
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Osmolar Concentration
MH  - Plasma Volume/*physiology
MH  - Rehydration Solutions/*chemistry/*therapeutic use
MH  - Rest/*physiology
MH  - Sodium/blood
MH  - *Space Flight
OTO - NASA
OT  - NASA Center ARC
OT  - NASA Discipline Regulatory Physiology
FIR - Greenleaf, J E
IR  - Greenleaf JE
IRAD- NASA ARC
EDAT- 1998/09/16 00:00
MHDA- 1998/09/16 00:01
CRDT- 1998/09/16 00:00
PHST- 1998/09/16 00:00 [pubmed]
PHST- 1998/09/16 00:01 [medline]
PHST- 1998/09/16 00:00 [entrez]
PST - ppublish
SO  - Aviat Space Environ Med. 1998 Sep;69(9):837-44.