Why You Need More Dietary Magnesium If You Exercise

Why You Need More Dietary Magnesium If You Exercise

There’s a mineral your body requires to run hundreds of chemical reaction inside your body – magnesium. Unfortunately, so much emphasis is placed on getting enough calcium that we don’t always track how much magnesium we’re getting. Everyone needs dietary magnesium but you need to be even more aware of how much magnesium is in your diet if you exercise. Some studies suggest that not getting enough of this vital mineral can negatively impact exercise performance.

Dietary Magnesium and Exercise

According to research, athletes and people who endurance train may need more dietary magnesium in their diet than sedentary people. This isn’t surprising since magnesium activates enzymes involved in producing ATP, the source of energy muscles use for contraction. Magnesium is also important for healthy heart and nerve function. Some studies show magnesium helps reduce perceived exertion by its effects on the nervous system so you don’t feel like you’re working as hard at a given exercise intensity.

Other small studies show dietary magnesium deficiency negatively affects how your heart responds to endurance exercise. In one study, at a given exercise intensity, participants had a higher heart rate and maximal oxygen uptake during sub-maximal exercise when they were deficient in magnesium. In other words, their heart and lungs had to work harder when they were low in magnesium. Other small studies show supplementing with magnesium improves aerobic capacity and endurance exercise performance.

What about resistance exercise performance? Some evidence shows dietary magnesium is important here too, but the benefits are less clear. One study in men showed resistance training combined with magnesium increased testosterone levels and had a performance-enhancing effect.

Magnesium is Important for Energy Production

Why is dietary magnesium so important if you exercise? Animal studies show low magnesium levels make the production of ATP by cellular mitochondria less efficient so less ATP is produced for a given amount of oxygen. Some studies show low levels of magnesium affect how muscles contract and relax, thereby increasing the energy cost of muscle contractions. These factors all impact exercise performance.

Can magnesium slow down the physical aging process? Too many people experience a decline in physical capabilities, the ability to be active and do the things they enjoy, with age. A new study published in the American Journal of Clinical Nutrition shows magnesium helps improve physical performance in older people. In this study involving 124 healthy women with an average age of around 70, those who took magnesium oxide for 12 weeks performed better on tests measuring functional capacity including walking speed and chair stand times. The benefits were more dramatic in participants who already had a low or borderline magnesium level.

Metabolic Benefits of Magnesium

Magnesium may be important for metabolic health as well, especially if you have type 2 diabetes. Studies show supplementing with magnesium improves blood glucose control in diabetics. Dietary magnesium improves insulin sensitivity, something that’s important for metabolic health. As a result, more doctors are recommending that patients with type 2 diabetes and metabolic syndrome add more magnesium to their diet. As a bonus, some research shows magnesium helps with blood pressure control and prevention of migraine headaches. Magnesium also works in conjunction with calcium to support healthy bones.

Are You Getting Enough Magnesium?

If you work out, your magnesium requirements may be higher. When you do a strenuous workout, you lose magnesium through sweat and in your urine. According to one study, this alone increases magnesium requirements by 10 to 20%. If you’re exercising in a hot environment, you may lose a significant amount of magnesium through sweating alone.

Don’t assume more magnesium is better. Evidence doesn’t show taking supplemental magnesium when you’re already meeting your requirements will improve your exercise performance. It means you should get enough magnesium in your diet to meet your magnesium requirements and replace the amount you lose through sweating.

Dietary Sources of Magnesium

The average person doesn’t need a magnesium supplement to meet their daily magnesium requirements. Some of the best sources of dietary magnesium are seeds and nuts. Roasted pumpkin seeds are a stand-out source with over 600 milligrams of magnesium in a half cup. Almonds have around 150 milligrams per 2-ounce serving. Walnuts, Brazil nuts, cashews, and sesame seeds are also rich in magnesium. Whole grain cereals, legumes like lentils and green, leafy vegetables are other good sources. Most adults need between 310 and 420 milligrams of magnesium daily. Athletes should shoot for the upper end of the range.

Symptoms of a low magnesium level include fatigue, irritability, problems sleeping and muscle cramps. In severe cases, you can have an abnormal heart rhythm. Certain health problems like inflammatory bowel disease, an overactive thyroid, diabetes, and kidney disease increase the risk for magnesium deficiency. Stress, heavy menstrual bleeding, drinking too much coffee or soda and eating a high-sodium diet can also lower your magnesium level. If you take certain medications, particularly diuretics, you lose magnesium in your urine. If you fall into one of these categories you may need a supplement, but talk to your doctor first. Otherwise, add more dietary magnesium-rich foods to your diet.

The take-home message? Make sure you’re getting enough magnesium in your diet. After all, it’s involved in over 300 cellular reactions, including ones involved in energy production. Don’t underestimate its importance in your diet, especially if you exercise.



J Nutr 132:930-935 (2002)
World’s Healthiest Foods website.
The Nutritionist. Robert Wildman, Ph.D., RD. Hawthorn Press (2002)
University of Maryland Medical Center. “Magnesium”
The American Journal of Clinical Nutrition. 2014, July 9. Ajcn.080168.
Magnes Res. 2006 Sep;19(3):180-9.
Nutrients 2013, 5, 3910-3919; doi:10.3390/nu5103910.
Poloquin Group. “Twelve Benefits of Magnesium”
J Sports Sci Med. Mar 2013; 12(1): 144-150.


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