Magnesium sulfate enhances exercise performance and manipulates dynamic changes in peripheral glucose utilization

Abstract

The effect of magnesium supplementation on exercise performance remains controversial. In the present study, the effects of magnesium sulfate on exercise performance and blood glucose metabolism were examined. In order to provide a non-invasive measure of continuous exercise, we developed an auto-blood sampling system was coupled to a microdialysis analyzer to detect the dynamic changes in glucose metabolism in conscious and freely moving gerbils subjected to forced swimming. Gerbils were pretreated with saline or magnesium sulfate (90 mg kg(-1), ip) 30 min before exercise. The duration times were significantly increased by 71% in the magnesium sulfate-treated groups (p < 0.01) when compared with those in the control. Another group of gerbils were subjected to blood sampling assay. A catheter was implanted in the jugular vein of each gerbil for collecting blood samples by the computer-aided blood sampler. The basal levels of plasma glucose, lactate, and magnesium were 6,245 +/- 662, 1,067 +/- 309, and 590 +/- 50 microM, respectively, with no significant difference between groups. Plasma glucose, lactate, and magnesium levels increased to 134 and 204%, 369 and 220%, and 155 and 422% of basal levels during swimming in both the control and magnesium sulfate-treated groups, respectively (p < 0.05). Pretreatment with magnesium sulfate elevated glucose and magnesium levels to 175 and 302% of the basal levels (p < 0.05), respectively, whereas pretreatment with magnesium sulfate reduced the lactate levels 150% of the basal level (p < 0.05) during swimming. Furthermore, the magnesium levels increased to about 152-422% of basal levels during forced swimming and the recovery period (p < 0.05). The present study demonstrates that magnesium sulfate improved the duration time of forced swimming exercise. In addition, magnesium raised glucose levels and attenuated lactate levels during forced swimming. These results indicate that positive effects of magnesium supplementation may contribute to the enhancement of exercise performance in athletes.

Relationship between the Effect of Dietary Fat on Swimming Endurance and Energy Metabolism in Aged Mice

“…The observation of significant increases in plasma Mg, Ca, and P levels after exhaustive swimming in aged mice is supported by studies that involved similar exercises in other animal experiments [19,40,41]. The swimming exercise may trigger the release of these minerals because of increased energy production and muscle contraction.…”

“…Moreover, minerals such as magnesium, calcium, phosphorus, and iron are present in animal bodies and act as cofactors for enzymes involved in energy production, muscle contraction, and nerve excitation as well as, in the case of iron, the oxygen-carrying capacity of blood [17]. Many studies [18,19,20,21] have reported a relationship between the status of minerals and exercise capacity in animals and humans. These factors may therefore influence alterations in swimming endurance caused by dietary fat.…”

SLC41A1, a Na+/Mg2+ exchanger, is downregulated during exercise

“…The Mg content in leukocytes is higher than that of mononuclear blood cells, which may represent the downregulation of SLC41A1 expression in blood. In our previous studies, plasma Mg concentrations increase in various treadmill exercise modes (5,6). Thus far, it may be concluded that the SLC41A1 gene expression is associated with blood pressure and blood Mg content.…”

“…Relatively large amounts of blood (>400 µl) collected in a short period may have also affected the SLC41A1 gene expression in the blood. In addition, plasma or serum Mg levels were not determined, although results of previous experiments have shown that plasma Mg levels in the blood rise ~20% following exercise (5,6). Furthermore, the SLC41A1 gene expression may vary in different parts of the body.…”

“…Furthermore, Mg supplements have been reported to improve athletic performance, and a short-term, high-intensity exercise has been shown to increase plasma Mg concentrations (4). Numerous studies have been conducted on the beneficial effects of Mg in exercise (4)(5)(6), but the associations between exercise and the gene expression of Mg-sensitive genes have not been studied. The solute carrier (SLC) family 41 member A1 (SLC41A1) protein was first identified by Wabakken et al (7), and then validated as a Mg transporter by Goytain and Quamme (8).…”