Premium
Correction of exercise‐induced sweat calcium loss in pre‐menopausal women
Author(s) -
Martin Berdine R.,
Weaver Connie,
Davis Shelly,
Bendich Adrianne
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a991-c
Subject(s) - sweat , calcium , placebo , crossover study , medicine , endocrinology , excretion , urine , urinary calcium , chemistry , zoology , biology , alternative medicine , pathology
Exercise‐induced sweat calcium losses have been reported as substantial in male athletes. The aim of this study was to determine exercise‐induced calcium sweat loss and to determine the effectiveness of calcium supplements to reverse any losses in physically active women. Twenty‐six pre‐menopausal sportswomen completed three 9‐day intervention phases in a randomized‐order, crossover design. The three intervention phases were placebo + no exercise (P+NEx), placebo + exercise (P+Ex), and 400 mg Ca as Ca Carbonate (TUMS Ultra®) twice daily + Ex. The supervised exercise was 1 hr cycling at 65%VO 2 heart rate reserve which was determined by a VO 2 sub‐max cycle ergometer test. A controlled diet of approximately 400 mg Ca/day and 24 hour pooled urine and fecal collections allowed determination of calcium balance on days 5–8 of each phase. Twenty‐four hour sweat collections were made at the end of each phase using a whole body washdown procedure. Exercise significantly (P<0.05) increased calcium losses in sweat (P+Ex, 93 +/‐51 vs. P+NEx 79+/‐31) which was no longer significant (P=0.14)when Ca supplementation was provided (84+51 mg/d). Significantly (P<0.01) higher urinary Ca excretion during calcium supplementation is suggestive of higher Ca absorption. Exercise had no effect on urinary Ca excretion indicating lack of compensation for sweat losses. Calcium intake should be increased by more than 70 mg/d to offset sweat losses during each single hour of moderate exercise. Funded by GlaxoSmithKline Consumer Health Care.