| Acute calcium ingestion attenuates exercise-induced disruption of calcium homeostasis. | |
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MedLine Citation:
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PMID: 20798655 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: Exercise is associated with a decrease in bone mineral density under certain conditions. One potential mechanism is increased bone resorption due to an exercise-induced increase in parathyroid hormone (PTH), possibly triggered by dermal calcium loss. The purpose of this investigation was to determine whether calcium supplementation either before or during exercise attenuates exercise-induced increases in PTH and C-terminal telopeptide of Type I collagen (CTX; a marker of bone resorption). METHODS: Male endurance athletes (n = 20) completed three 35-km cycling time trials under differing calcium supplementation conditions: 1) 1000 mg of calcium 20 min before exercise and placebo during, 2) placebo before and 250 mg of calcium every 15 min during exercise (1000 mg total), or 3) placebo before and during exercise. Calcium was delivered in a 1000-mg·L(-1) solution. Supplementation was double-blinded, and trials were performed in random order. PTH, CTX, bone-specific alkaline phosphatase (BAP; a marker of bone formation), and ionized calcium (iCa) were measured before and immediately after exercise. RESULTS: CTX increased and iCa decreased similarly in response to exercise under all test conditions. When compared with placebo, calcium supplementation before exercise attenuated the increase in PTH (mean ± SE: 55.8 ± 15.0 vs 74.0 ± 14.2 pg·mL(-1), P = 0.04); there was a similar trend (58.0 ± 17.4, P = 0.07) for calcium supplementation during exercise. There were no effects of calcium on changes in CTX, BAP, and iCa. CONCLUSIONS: Calcium supplementation before exercise attenuated the disruption of PTH. Further research is needed to determine the effects of repeated increases in PTH and CTX on bone (i.e., exercise training) and whether calcium supplementation can diminish any exercise-induced demineralization. |
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Authors:
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Daniel W Barry; Kent C Hansen; Rachael E van Pelt; Michael Witten; Pamela Wolfe; Wendy M Kohrt |
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Publication Detail:
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Type: Journal Article; Randomized Controlled Trial; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Medicine and science in sports and exercise Volume: 43 ISSN: 1530-0315 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 2011 Apr |
Date Detail:
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Created Date: 2011-03-17 Completed Date: 2011-07-29 Revised Date: 2012-04-04 |
Medline Journal Info:
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Nlm Unique ID: 8005433 Medline TA: Med Sci Sports Exerc Country: United States |
Other Details:
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Languages: eng Pagination: 617-23 Citation Subset: IM; S |
Affiliation:
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Department of Medicine, Division of General Internal Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA. daniel.barry@ucdenver.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Bicycling Calcium, Dietary / administration & dosage*, pharmacology Double-Blind Method Exercise / physiology* Homeostasis / drug effects* Humans Male Parathyroid Hormone / metabolism* Sweat / chemistry |
| Grant Support | |
ID/Acronym/Agency:
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1 UL1 RR 025780/RR/NCRR NIH HHS; P30 DK048520-16/DK/NIDDK NIH HHS; P30 KD048520//PHS HHS; UL1 RR025780-01/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Calcium, Dietary; 0/Parathyroid Hormone |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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