The Effects of High-Impact and Resistance Exercise on Urinary Calcium Excretion

Tricia Nemoseck, Mark Kern
2009 International Journal of Sport Nutrition & Exercise Metabolism  
Although physical activity is known to improve bone mineralization, it is unclear whether this occurs through altered absorption and/or excretion. The purpose of this study was to investigate the effects of a high-impact and resistance-training exercise program versus a period of restricted physical activity on urinary calcium excretion. Ten healthy, moderately active men (27.0 ± 5.8 yr) participated in a 3-wk randomized crossover study. Participants were assigned to complete either a period of
more » ... either a period of daily participation in exercise including high-impact and resistance-training activities (EX) or a period of restriction in physical activity (NE) for 7 consecutive days. After a 1-wk washout period, participants completed the opposite trial. During both phases, participants consumed four 8-oz servings of low-fat (1%) milk daily and avoided other dietary and supplemental sources of calcium. Urine was collected throughout the final 72 hr of each study phase. Urinary calcium and sodium excretions were 14.7% ± 17.1% and 15.8% ± 9.9% lower (p < .05), respectively, during the EX phase than the NE phase. These results occurred despite participants consuming more (p < .05) sodium during the EX phase than the NE phase. These results suggest that healthy, moderately active men excrete significantly less urinary calcium concurrent with lower sodium excretion during a week of performing high-impact and resistancetraining exercises versus a week of restricted physical activity. The reduction in urinary loss of calcium might be at least partially responsible for improved bone mineralization that has been observed during periods of greater physical activity. Osteoporosis is a condition of reduced bone mass that results in increased bone fragility and fractures (Flynn, 2003) . Approximately 10 million Americans have been diagnosed with osteoporosis, and it has been estimated that one in two women and one in four men over the age of 50 years will have an osteoporosisrelated fracture in their lifetime (Hampton, 2004) . Adequate intake of dietary calcium and participation in physical activity are vital factors in the development of The authors are with the
doi:10.1123/ijsnem.19.2.162 pmid:19478341 fatcat:7c354aayevgezcopotxyufkf2a