Weller E, Bachert P, Meinck H M, Friedmann B, Bärtsch P, Mairbäurl H
Department of Sports Medicine, University of Heidelberg, Germany.
Med Sci Sports Exerc. 1998 Nov;30(11):1584-91. doi: 10.1097/00005768-199811000-00005.
Magnesium (Mg) is important for regulating ion transport and cellular metabolism in all body tissues. In skeletal muscle Mg is involved in the neuromuscular activity, excitation, and muscle contraction. Mg deficiency can cause muscle weakness and muscle cramps. Less than 1% of total body Mg is found in serum, yet the serum Mg concentration is used to assess the body's Mg status.
The purpose of this study was to determine whether an oral Mg supplementation (500 mg Mg-oxide.d-1 for 3 wk) affects exercise performance, clinical symptoms, and the Mg concentration in various body compartments in athletes with low-normal serum Mg levels (N = 10 in each group).
In a double-blind, placebo-controlled study, correlation analysis between the Mg concentration in serum, blood cells, and skeletal muscle was performed to establish a measure for muscle cell Mg.
The data indicate that a 3-wk Mg supplementation did not affect exercise performance, neuromuscular activity, or muscle related symptoms. Also, the supplementation did not increase the Mg concentration in serum or any cellular compartment studied. However, in the placebo group the renal Mg clearance decreased, whereas it increased in the subjects receiving Mg supplementation. Correlation analysis revealed that serum Mg only correlated with red cell Mg and that only leukocyte Mg correlated with the nuclear magnetic resonance (NMR)-measured muscle cell Mg concentration.
These results indicate that Mg supplementation in athletes with low-normal serum Mg did not improve performance and failed to increase the body's Mg stores. Serum Mg appears to be a poor indicator for Mg in skeletal muscle or most other cellular compartments, but the concentration of Mg in mononuclear leukocytes might be used as an indicator of skeletal muscle Mg when NMR is not available.
镁（Mg）对于调节所有身体组织中的离子转运和细胞代谢至关重要。在骨骼肌中，镁参与神经肌肉活动、兴奋和肌肉收缩。镁缺乏会导致肌肉无力和肌肉痉挛。血清中镁的含量不到全身镁总量的1%，但血清镁浓度用于评估身体的镁状态。
本研究的目的是确定口服补充镁（氧化镁500毫克/天，持续3周）是否会影响血清镁水平略低的运动员（每组N = 10）的运动表现、临床症状以及不同身体部位的镁浓度。
在一项双盲、安慰剂对照研究中，对血清、血细胞和骨骼肌中的镁浓度进行相关性分析，以建立肌肉细胞镁的测量方法。
数据表明，为期3周的镁补充对运动表现、神经肌肉活动或肌肉相关症状没有影响。此外，补充镁并未增加血清或所研究的任何细胞部位的镁浓度。然而，在安慰剂组中，肾脏镁清除率下降，而在接受镁补充的受试者中则上升。相关性分析显示，血清镁仅与红细胞镁相关，只有白细胞镁与核磁共振（NMR）测量的肌肉细胞镁浓度相关。
这些结果表明，血清镁水平略低的运动员补充镁并不能提高运动表现，也未能增加身体的镁储备。血清镁似乎不是骨骼肌或大多数其他细胞部位镁含量的良好指标，但在无法进行核磁共振检查时，单核白细胞中的镁浓度可能用作骨骼肌镁含量的指标。
