| Renal, endocrine, and cardiovascular responses to bed rest in male subjects on a constant diet. | |
| | |
MedLine Citation:
|
PMID: 15068228 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
BACKGROUND: Exposure to actual and simulated microgravity induces cardiovascular deconditioning through a variety of factors. Although the mechanisms involved remain uncertain, one involves alterations in volume-regulating systems--the hypothesis being tested in this study. To maximize our ability to detect subtle changes in the volume-regulating systems, subjects were studied on a high-average salt intake to maximally suppress these systems basally. METHODS: Fourteen healthy male subjects underwent 14-day head-down tilt bed rest (HDTB) during which a constant 200 mEq sodium, 100 mEq potassium diet was maintained. Daily 24-hour urine collection was performed; plasma renin activity, serum aldosterone, plethysmography, and cardiovascular system identification were performed during a control period (pre-HDTB) and at the end of HDTB (end HDTB). RESULTS: Sodium excretion increased initially (pre-HDTB = 182.8 +/- 10.4 mEq/total volume; early HDTB = 236.4 +/- 13.0; p = .002) and then returned to baseline values. Potassium excretion increased 4 days after the initiation of HDTB and remained elevated thereafter (pre-HDTB = 82.2 +/- 2.4/total volume; mid- to late HDTB = 89.4 +/- 2.1; p = .02). Plasma renin activity increased significantly with HDTB (pre-HDTB = 1.28 +/- 0.21 ng/mL/h; end HDTB = 1.69 +/- 0.18; p = .01), but serum aldosterone did not change. A significant decrease in autonomic responsiveness and an increase in leg compliance were observed. CONCLUSIONS: We conclude that even in the presence of a high-average salt intake diet, simulated microgravity leads to renal, cardioendocrine, and cardiovascular system alterations that likely contribute to cardiovascular deconditioning. |
| | |
Authors:
|
S Marlene Grenon; Natalie Sheynberg; Shelley Hurwitz; Grace Xiao; Craig D Ramsdell; Michael D Ehrman; C Lan Mai; Siri Rostoft Kristjansson; Grete H Sundby; Richard J Cohen; Gordon H Williams |
Related Documents
:
|
23034408 - Availability of supervised exercise programs and the role of structured home-based exer... 21143878 - Green tea polyphenols supplementation and tai chi exercise for postmenopausal osteopeni... 16845458 - Georges dreyer (1873-1934) and a forgotten episode of respiratory physiology at oxford. 16555198 - Hybridization among divergent stocks of largemouth bass (micropterus salmoides) results... 23666438 - Telerehabilitation for people with chronic obstructive pulmonary disease: feasibility o... 10710498 - Hepatic alpha- and beta-adrenergic receptors are not essential for the increase in r(a)... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Journal of investigative medicine : the official publication of the American Federation for Clinical Research Volume: 52 ISSN: 1081-5589 ISO Abbreviation: J. Investig. Med. Publication Date: 2004 Mar |
Date Detail:
|
Created Date: 2004-04-07 Completed Date: 2004-04-20 Revised Date: 2007-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 9501229 Medline TA: J Investig Med Country: Canada |
Other Details:
|
Languages: eng Pagination: 117-28 Citation Subset: IM; S |
Affiliation:
|
Division of Endocrinology, Brigham and Women's Hospital, Boston, MA 02115, USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adult Bed Rest Cardiovascular Deconditioning / physiology* Endocrine System / physiology* Head-Down Tilt / physiology Hemodynamics Humans Immobilization / physiology* Kidney / physiology* Leg / blood supply Male Plethysmography Potassium / urine Renin-Angiotensin System / physiology Sodium / urine Sodium Chloride, Dietary Veins / physiology Weightlessness / adverse effects* |
| Grant Support | |
ID/Acronym/Agency:
|
5M01RR02635/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Sodium Chloride, Dietary; 7440-09-7/Potassium; 7440-23-5/Sodium |
| Investigator | |
Investigator/Affiliation:
|
R J Cohen / MA Inst Technol, Cambridge, MA; G H Williams / Brigham & Women's Hosp, Boston, MA |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Implementation of community consultation for waiver of informed consent in emergency research: one I...
Next Document: Fatty acids differentially modulate insulin-stimulated endothelial nitric oxide production by an Akt...