Document Detail

Acute calcium ingestion attenuates exercise-induced disruption of calcium homeostasis.
MedLine Citation:
PMID:  20798655     Owner:  NLM     Status:  MEDLINE    
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.
Daniel W Barry; Kent C Hansen; Rachael E van Pelt; Michael Witten; Pamela Wolfe; Wendy M Kohrt
Related Documents :
12471325 - Exercise effects on fitness and bone mineral density in early postmenopausal women: 1-y...
16926125 - Exercise distance and speed affect the risk of fracture in racehorses.
18378195 - Exercise during childhood and adolescence: a prophylaxis against cystic fibrosis-relate...
12689685 - Aerobic exercise and bone mineral density in middle-aged finnish men: a controlled rand...
17024635 - Monitoring 6 weeks of progressive endurance training with plasma glutamine.
15792915 - Anemia and the elderly: clinical considerations.
Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
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:
Created Date:  2011-03-17     Completed Date:  2011-07-29     Revised Date:  2014-09-08    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  617-23     Citation Subset:  IM; S    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Calcium, Dietary / administration & dosage*,  pharmacology
Double-Blind Method
Exercise / physiology*
Homeostasis / drug effects*
Parathyroid Hormone / metabolism*
Sweat / chemistry
Grant Support
1 UL1 RR 025780/RR/NCRR NIH HHS; P30 DK048520/DK/NIDDK NIH HHS; P30 DK048520-16/DK/NIDDK NIH HHS; P30 KD048520//PHS HHS; UL1 RR025780/RR/NCRR NIH HHS; UL1 RR025780-01/RR/NCRR NIH HHS
Reg. No./Substance:
0/Calcium, Dietary; 0/Parathyroid Hormone

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

Previous Document:  Exercise Intensity Influences NEAT in Overweight and Obese Adults.
Next Document:  Lower extremity kinematics in runners with patellofemoral pain during a prolonged run.