Magnesium And Exercise Performance

Key Points

. A good nutrition and training plan are the TOP priorities in ensuring optimal exercise performance and output.

. Supplements can be added ONLY once an optimal nutrition and training plan has been establishe. 

. Even with a great nutrition plan, exercise demands on the body may require additional supplementation in order to maintain a high level of quality exercise output (and health!). 

. Magnesium supplementation might be beneficial for improving exercise performance through enhacing glucose transport into muscle cells and ensuring rapid lactate clearance from muscles. 

Magnesium And Glucose

Increasing exercise performance is always a popular topic amongst clients. After all, if you have a goal (e.g. getting stronger, fitter, leaner), than exercise (alongside nutrition) is going to be your means to achieve that goal. Is is not a surprise then that people become interested in ways of maximising their exercise output as much as possible. At the end of the day, increased exercise performance is only going to increase the speed and extent of the progress you can potentially make. One question I frequently come across with clients is: are there any supplements I can take to increase my exercise performance? Well, first things first: the best performance gains are going to come primarily through proper training programming and nutrition. Only when you have a firm grasp on these two things can you begin to start thinking about supplements. However, even with great nutrition and training, supplements can help fill in the gaps. Even if your nutrition can provide you with everything you need, regular exercise is likely to demand even more in the way of nutrients. As a result, regular nutrition might not be able to keep up with the nutrient supply your body demands during increased exercise. In these circumstances, supplementation might be a sensible thing to consider.

One such nutrient that gets used up considerably during exercise is magnesium. Now, if your diet is optimal, then you will be able to acquire all the magnesium you need to stay functioning optimally. Foods particularly rich in magnesium are spinach, nuts and seeds, beans and bananas. However, during exercise, a large amount of magnesium can be lost in sweat and urine. If you exercise regularly and intensely, you are going to lose quite a bit of magnesium. Even if your diet is good, it might not be able to supply the magnesium you need fully to keep pace with the extent of your exercise regime. If this is the case, you might find yourself becoming depleted in sufficient magnesium over time to maintain optimal exercise performance (and of course health!). In this case then, supplementation with magnesium might be a sensible thing to do!

An important question to ask then is: what is the link between magnesium and exercise performance? Well, we know that magnesium plays a central role in glucose metabolism. Since glucose provides the fuel needed to make our muscles work, efficient regulation of glucose is going to be the driver of optimal exercise performance. Energy in the body is stored as glycogen within the muscles and liver. When we exercise, this glycogen is then broken down into glucose. Once glucose is available, it needs to be shuttled into muscle for utilisation. This glucose can then be utilised to provide ATP, the energy currency for your muscles. Recently, researchers have suggested that magnesium helps increase the efficiency of glucose uptake into muscle cells. This of course is advantageous because it means that your muscle cells can get ready access to the energy they need to function at an optimal level during activity.

Chen et al. (2018): The Effect Of Magnesium On Exercise Performance Via Glucose And Lactate Regulation

The importance of magnesium for optimal exercise performance was recently studied by Chen et al. (2018). In this study, Sprague-Dawley rats were pre-treated with either saline solution (contains no magnesium) or a magnesium-sulfate solution 30 minutes before a treadmill exercise activity. This consisted of an exercise speed of 20 m/min for 60 minutes. Following the exercise procedure, muscle samples were taken through microdialysis to measure the levels of glucose and lactate present in the controls (saline) and magnesium treated rats.

Firstly, within the control group, muscle glucose concentrations rose to 300-440% of basal levels during exercise, while in the magnesium-treated group, there was an 650%-780% increase above basal levels during exercise in muscle glucose. During recovery, muscle glucose concentrations dropped to approx. 200% of basal levels in both groups 15-30 minutes during the recovery period. Furthermore, muscle lactate levels in the control group rose sharply to approx. 430% of basal levels and reached 600% at the beginning of exercise. Within 30 minutes following exercise, muscle lactate levels had dropped to approx. 360% of basal levels. Even after this period, muscle lactate remained at approx. 300% above basal levels. In the magnesium-treated group, there was a 45 minute delay in this muscle lactate elevation. Peak levels were 500% of basal levels and during the recovery period, there was a rapid decrease in muscle lactate to approx. 260% of basal levels and continued to drop back to basal levels.

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Figure by Chen et al. (2018). Comparison of muscle glucose concentration changes during and post-exercise between rats administered with either saline or magnesium solution. In rats given magnesium solution, there was a rapid initial rise in muscle glucose concentrations above baseline, which remained significantly elevated during the exercise session in comparison to those administered with just saline. 

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Figure by Chen et al. (2018). Comparison shows the changes in muscle lactate concentrations between those rats given either saline or magnesium pre-exercise. In those given magnesium, there is a delayed increase in muscle lactate as well as a rapid clearance back to baseline following exercise in comparison to those administered saline. 

So what are these results saying? Well, it is clear that magnesium is helping glucose to get into the muscle cells in some way. One of the major transporters which help shuttle glucose into the muscle cells from the blood is the GLUT4 transporter. Interestingly, past studies have demonstrated that in the absence of magnesium, expression of the GLUT4 transporter is significantly downregulated. However, when magnesium is administered, expression of the GLUT4 transporter is increased. Furthermore, magnesium is suggested to also interact with insulin to help further optimise transport of glucose via this GLUT4 receptor. It is possible then that in this study, the application of magnesium improved the expression of GLUT4 (as well as a possible interaction with insulin), in turn improving the delivery of glucose to muscle cells. However, the regulation of lactate is also interesting. The buildup of lactic acid within the muscles during exercise can significantly hinder the efficiency of muscle performance and muscular contractions. Muscle lactate can be transported into the blood by monocarboxylate transporters (MCTs). It is possible that magnesium improves the efficiency of these MCTs speeding up the clearance of muscle lactate. Not only would this help prevent loss of muscle performance during exercise, it would also speed up post-exercise recovery.

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It is important to keep a few things in mind with this study:


  • This study was conducted in rats not humans. Although this study gives us interesting insights into the potential role of magnesium in exercise performance, it is impossible to know for sure whether these same observations would translate directly into humans. Next stop, human studies!
  • Directly testing exercise performance outcomes were not measured. While we can assume that better glucose regulation within muscle cells can improve exercise output and efficiency, exercise output and efficiency were not actually tested here.
  • We don’t know the exact mechanisms by which magnesium is working. While past studies have identified a possible link between magnesium and GLUT4 and MCTs, this link was not further studied in this study. More work needs to be done to elucidate the exact mechanisms by which magnesium is working to optimise glucose and lactate regulation in muscle cells.


Magnesium Has Potential!

Still early days, but it seems that magnesium has the potential to improve your exercise output! From this recent study, two things are clear: 1) magnesium can help get glucose into your muscles efficiency, and a lot more of it! Ultimately, your muscles get the fuel it needs to perform at their best, and 2), magnesium can help delay lactic acid build up as well as allow for its rapid clearance following exercise. This not only keeps your muscles functioning at their best during the exercise session, it allows them to optimally recover during the post-exercise period. Both are important if you want to keep performing at your very best! But, at this present time, the precise mechanisms are unknown, but ideas are floating around with regards to interaction with specific transporters. For now, we will have to wait for specific studies investigating these potential mechanisms.

Getting in everything you need for optimal health and performance should come from your nutrition. However, exercise (e.g. the type, frequency and intensity) can change the demands placed on the body for certain nutrients. Therefore, supplementation of these key nutrients might help keep you on the optimal path than nutrition alone. From this latest study, magnesium seems like a good thing to supplement, especially if you are exercising a lot and want to keep exercising at an optimal level. Hopefully, more studies will follow to elucidate the exact mechanisms by which magnesium works to increase exercise performance.


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