Document Detail

Sex hormone effects on body fluid and sodium regulation in women with and without exercise-associated hyponatremia.
MedLine Citation:
PMID:  19556454     Owner:  NLM     Status:  MEDLINE    
We hypothesized that exercise-associated hyponatremia (EAH) is a function of excess sodium loss combined with high water intake in women at risk for dysnatremias during endurance exercise. We further hypothesized that estradiol and progesterone exposure increases fluid retention and sodium loss during exercise in women at risk for EAH. For 16 days we suppressed estrogens and progesterone with a gonadotropin-releasing hormone antagonist (GnRH ant) in seven women with (Hypo) and nine women without (no Hypo) a history of hyponatremia; we added 17beta-estradiol (0.2 mg/day patches) for days 4-16 (E(2)) and progesterone (200 mg/day) for days 13-16 (E(2)-P(4)). Under each hormone condition, subjects cycled in 35 degrees C at 65% peak oxygen consumption (Vo(2peak)) for 60 min, then at 55-60% Vo(2peak) for 120 min. Subjects drank 8 ml/kg of water (and replenished urine volume) every 30 min over the final 120 min of exercise. S([Na+]) fell by 4.3, 3.9, and 3.1 meq/l (P < 0.05) with drinking during GnRH ant, E(2), and E(2)-P(4) in Hypo, with little fall in no Hypo. Under all conditions, combined urine and sweat sodium loss were similar between Hypo [-85.6 (SD 36.2), -86.4 (SD 39.2), and -112.0 (SD 30.0) meq] and no Hypo [-98.0 (SD 54.8), -80.9 (SD 57.6), and -105.1 (SD 46.4) meq, for GnRH, E2, and E2-P4], as was mass balance of electrolytes (E(MB)) for Hypo [-104.8 (SD 32.8), -103.6 (SD 42.1), and -132.8 (SD 34.9) meq] compared with no Hypo [-128.8 (SD 57.2), -113.5 (SD 61.1), and -143.4 (SD 49.6) meq for GnRH, E2, and E2-P4]. Mass balance of water [V(MB), for Hypo, 0.42 (SD 0.10), 0.62 (SD 0.25), and -0.11 (SD 0.11) liter] compared with no Hypo [0.01 (SD 0.15), 0.03 (SD 17), and -0.16 (SD 0.13) liter for GnRH, E2, and E2-P4, P < 0.05] indicates water retention was the primary contributor to the lower S([Na+]) in Hypo women.
Nina S Stachenfeld; Hugh S Taylor
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-06-25
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  107     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2009 Sep 
Date Detail:
Created Date:  2009-08-28     Completed Date:  2009-10-05     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  864-72     Citation Subset:  IM    
The John B. Pierce Laboratory, Yale University School of Medicine, New Haven, Connecticut 06519, USA.
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MeSH Terms
Body Fluids / physiology*
Electrolytes / metabolism
Estradiol / pharmacology
Exercise / physiology*
Exercise Test
Gonadal Steroid Hormones / pharmacology*
Gonadotropin-Releasing Hormone / antagonists & inhibitors
Hormone Antagonists / pharmacology
Hyponatremia / physiopathology*
Osmolar Concentration
Oxygen Consumption / drug effects,  physiology
Progesterone / pharmacology
Sodium / metabolism*
Sweating / physiology
Water-Electrolyte Balance / drug effects,  physiology
Young Adult
Reg. No./Substance:
0/Electrolytes; 0/Gonadal Steroid Hormones; 0/Hormone Antagonists; 33515-09-2/Gonadotropin-Releasing Hormone; 50-28-2/Estradiol; 57-83-0/Progesterone; 7440-23-5/Sodium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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