Magnesium: Its effect on sports, exercise and fitness

For professional athletes, milliseconds can decide between victory and defeat. In endurance sports, continuous performance is important, while in tactical sports, optimal cooperation between body and mind is important. Many athletes try to support their performance with nutritional supplements. But what is the truth behind the alleged effect of magnesium? And do athletes really need magnesium as a nutritional supplement?  

Table of contents 

• What is magnesium?
• How much magnesium do athletes need per day?
• What dosage is recommended for magnesium?
• What side effects can magnesium supplements have?
• Which form of magnesium should be taken?
• Myth of magnesium and sore muscles: Can magnesium relieve it?
• Myth about magnesium and cramps: Can magnesium prevent them?
• Conclusion

What is magnesium? 

Magnesium is one of the so-called essential nutrients, along with many other vitamins and minerals. This means that the human organism cannot produce magnesium itself, but needs it to survive. This is because magnesium is involved in more than 300 metabolic reactions. Without an adequate supply of magnesium, normal energy metabolism cannot be maintained. And this has a direct impact on athletic performance. 

Did you know that…? 

Magnesium is involved in both the relaxation and contraction of skeletal, cardiac, vascular and uterine muscles. 

How much magnesium do athletes need per day? 

The best way to meet your daily magnesium needs is through a balanced, healthy diet. Many foods are rich in magnesium. However, you should remember that long cooking with a lot of water has a negative effect on the magnesium content. Food components such as phytic acid in grains or oxalic acid in rhubarb can also inhibit absorption. Experts therefore recommend regularly varying the foods you eat. 

Magnesium content of various foods 

Groceries	Milligrams of magnesium per 100 grams
Pumpkin seeds	535
Dark chocolate	290
Peanuts	163
Wholemeal bread	90
Wholegrain pasta	125
Normal noodles	40
mineral water	Between 50 and 100
Bananas	36
Peas	33
broccoli	24

The official intake recommendation of the German Nutrition Society (DGE) is for women over 25 years of age, 300 mg of magnesium per day . For men, the DGE gives a reference value of 350 mg per day. Special life circumstances can slightly increase the requirement. These include pregnancy and breastfeeding, stress, frequent use of laxatives, high alcohol consumption and competitive sports.  

What dosage is recommended for magnesium? 

There are no clear intake recommendations for athletes. The magnesium requirement depends heavily on the food consumed and the daily magnesium loss. This can be increased particularly through sweating. Here, experts assume that a sweat loss of 2 liters corresponds to a loss of magnesium of around 10 mg. With an average bioavailability of 35 percent, the additional magnesium requirement corresponds to 30 mg. 

Athletes also have the option of having their magnesium levels tested by a doctor. Usually, however, only the magnesium level in the blood serum is measured. This is not very informative about the general magnesium reserves, as the magnesium level in the plasma is only reduced when there is a severe deficiency. This is primarily because the body can compensate for insufficient magnesium intake for a long time using its own reserves. 

3 common signs of magnesium deficiency 

• Muscle tremors 
• Muscle weakness 
• Muscle cramps 

In addition, there are many other, sometimes non-specific symptoms such as fatigue, headaches, tension in the shoulder and neck area or cold hands and feet. 

What side effects can magnesium supplements have? 

Like almost all dietary supplements, magnesium carries the risk of overdose. This is primarily manifested by unpleasant symptoms such as diarrhea, vomiting or dizziness. It can be more dangerous for people with kidney disease. In these cases, an overdose can lead to life-threatening magnesium poisoning with respiratory paralysis. The same applies if extremely high amounts of magnesium are consumed in a short period of time. Since this is a medical emergency, medical help should be sought immediately. 

Which form of magnesium should be taken? 

It is important to know that magnesium is never present as a pure substance in food supplements, but always in a compound. This is because magnesium reacts quickly with other substances and materials due to its reactivity. 

There are various forms of magnesium available on the market. The best known is magnesium oxide . This is a very cheap raw material and is used by many manufacturers of dietary supplements. However, studies show that magnesium oxide has very poor bioavailability compared to other forms of magnesium (4). If you want to use a natural and plant-based magnesium preparation, you can take magnesium from sea lettuce. 

Myth of magnesium and sore muscles: Can magnesium relieve it? 

It is widely believed that magnesium helps prevent muscle soreness. But what does science say about this? 

There is no clear, strong "yes" yet, but there is a "very likely". A study from 2019 found that supplementing with 500 mg of magnesium per day reduced muscle soreness. However, performance and general regeneration were not improved (3). Another study from 2019, published in the renowned journal Nutrients , also came to the conclusion that magnesium has a protective effect on muscles during exercise. To achieve this effect, the athletes supplemented 400 mg of magnesium daily. It can therefore be assumed that magnesium can partially prevent muscle soreness. However, the exact mechanism of action is not yet fully understood and further studies are needed to answer the question with a strong "yes". 

Myth Magnesium and cramps:
Can magnesium prevent them? 

Another widespread myth is the connection between magnesium and muscle cramps. Magnesium relieves muscle cramps, doesn't it? 

According to current studies, the answer is no. For example, an increased magnesium intake of 20 mmol magnesium sulfate (5g) per day in a randomized, placebo-controlled study with 46 subjects did not lead to a significant improvement in muscle cramps. It must be acknowledged that the study participants were of advanced age and the magnesium was administered intravenously. Nevertheless, the authors conclude that, based on their study results, no recommendation should be made to take magnesium for cramps in older people (1). 

A meta-study from 2021 also comes to the conclusion that it is unlikely that magnesium makes a significant contribution to the prevention of muscle cramps. For this purpose, 11 studies with 735 subjects were analyzed and evaluated. However, most of the studies analyzed were conducted on older people. Unfortunately, the meta-study did not find any studies in the literature search that examined the effect on muscle cramps in athletes . There is a need for further research here and it remains unclear whether it can be scientifically proven whether magnesium can prevent cramps during exercise (2). 

Conclusion 

Magnesium is an essential mineral that is particularly important for athletes as part of a normal energy metabolism. The recommended daily intake of 300 - 400 mg of magnesium per day is best covered by a healthy, balanced diet. In times of increased need, taking a magnesium supplement can be useful. However, this should be supplemented specifically, preferably in consultation with a doctor, to avoid an overdose. If you want to use a natural and plant-based magnesium supplement, you can take magnesium from sea lettuce. 

Well-known assumptions such as "magnesium prevents muscle cramps" have not stood up to scientific research. Both individual studies and meta-studies have shown little or no effect on muscle cramps. However, taking magnesium supplements could prevent muscle soreness. 

Sources 

(1) Garrison SR, Birmingham CL, Koehler BE, McCollom RA, Khan KM. The effect of magnesium infusion on rest cramps: randomized controlled trial. J Gerontol A Biol Sci Med Sci. 2011 Jun;66(6):661-6. doi: 10.1093/gerona/glq232. Epub 2011 Feb 2. PMID: 21289017.

(2) Garrison SR, Korownyk CS, Kolber MR, Allan GM, Musini VM, Sekhon RK, Dugré N. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020 Sep 21;9(9):CD009402. doi: 10.1002/14651858.CD009402.pub3. PMID: 32956536; PMCID: PMC8094171.

(3) Steward CJ, Zhou Y, Keane G, Cook MD, Liu Y, Cullen T. One week of magnesium supplementation lowers IL-6, muscle soreness and increases post-exercise blood glucose in response to downhill running. Eur J Appl Physiol. 2019 Dec;119(11-12):2617-2627. doi: 10.1007/s00421-019-04238-y. Epub 2019 Oct 17. PMID: 31624951.

(4) Werner T, Kolisek M, Vormann J, Pilchova I, Grendar M, Struharnanska E, Cibulka M. Assessment of bioavailability of Mg from Mg citrate and Mg oxide by measuring urinary excretion in Mg-saturated subjects. Magnes Res. 2019 Aug 1;32(3):63-71. doi: 10.1684/mrh.2019.0457. PMID: 32162607.

(5) Uysal N, Kizildag S, Yuce Z, Guvendi G, Kandis S, Koc B, Karakilic A, Camsari UM, Ates M. Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best? Biol Trace Elem Res. 2019 Jan;187(1):128-136. doi: 10.1007/s12011-018-1351-9. Epub 2018 Apr 21. PMID: 29679349.

(6) Schuette SA, Lashner BA, Janghorbani M. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. JPEN J Parenter Enteral Nutr. 1994 Sep-Oct;18(5):430-5. doi: 10.1177/0148607194018005430. PMID: 7815675.