The importance of magnesium in body physiology and its recommended intake

MAGNESIUM PHYSIOLOGY

Magnesium Redistribution

During exercise, magnesium shifts from the serum to tissues such as red blood cells, muscle cells, and adipose tissue. This is influenced by metabolic demands, such as glycolysis in red blood cells and energy production in muscles. After exercise, magnesium is mobilized back into the plasma to restore balance, but this redistribution is affected by exercise intensity and muscle damage.

Magnesium Loss

Magnesium is lost through sweat and urine, with losses increasing during high-intensity or prolonged exercise. Sweat losses are significant, especially in hot environments, while urinary losses may result from metabolic acidosis (headaches, confusion, fatigue, tremors, drowsiness, asterixis, and brain dysfunction) and changes in renal tubular function.

Effects of Marginal Deficiency

A marginal deficiency can impair exercise performance, as shown in both animal and human studies. Symptoms include reduced endurance, increased oxygen consumption, and muscle cramps. Magnesium deficiency also increases oxidative stress and neuromuscular excitability due to disrupted calcium–magnesium balance within cells.

Exercise Performance

Magnesium supplementation benefits individuals with low magnesium levels by improving oxygen transport efficiency, muscle function, and endurance. Those with adequate magnesium levels experience little to no performance benefits from supplementation.

Immune and Cardiovascular Effects

Magnesium deficiency worsens exercise-induced immune suppression and increases cardiovascular risks, such as arrhythmias or potassium imbalances.

Oxidative Stress

Exercise-induced production of reactive oxygen species may be amplified by magnesium deficiency, potentially leading to muscle damage and systemic inflammation.

The Role of Magnesium in the Musculoskeletal System and Other Conditions

In bones, low magnesium weakens bone structure, promoting osteopenia and osteoporosis. In muscles, magnesium deficiency damages cellular structures such as the sarcoplasmic reticulum and mitochondria.

Clinical studies in postmenopausal women show that magnesium levels are lower in those with osteoporosis. However, short-term magnesium supplementation has been shown to improve bone markers, suggesting its potential to reduce bone loss.

Regarding other serious conditions, magnesium has been found to improve symptoms of headaches and migraines, Alzheimer’s disease, vascular disorders, hypertension, cardiovascular disease, type 2 diabetes, anxiety disorders, and sleep disturbances.

Magnesium-Rich Foods

Unprocessed whole grains, spinach, nuts, legumes, and potatoes are among the most important dietary sources of magnesium.

Supplement Intake

In individuals with marginal magnesium deficiency, doses of approximately 250–365 mg per day from supplements have been used to improve performance, enhance oxygen utilization during exercise, and restore muscle function.

Increased Requirements Due to Exercise

Magnesium requirements for individuals engaging in intense exercise may be 10–20% higher than those for sedentary individuals. For example, if the recommended daily intake for an average adult is approximately 300–400 mg, athletes may require 330–480 mg per day.

In studies, supplementation with 360 mg per day in female athletes with low plasma magnesium levels improved markers of muscle function.

In individuals consuming approximately 250 mg of magnesium daily (considered insufficient), adding an additional 250 mg per day improved exercise capacity and strength.

Individuals with Adequate Magnesium Levels

In cases where magnesium levels were already sufficient, no significant benefits were observed from supplementation.

Sources

Buchman, Alan L., et al. “The effect of a marathon run on plasma and urine mineral and metal concentrations.” Journal of the American College of Nutrition 17.2 (1998): 124-127.

Long S, Romani AM. Role of Cellular Magnesium in Human Diseases. Austin J Nutr Food Sci. 2014.

Stella Lucia Volpe, Magnesium in Disease Prevention and Overall Health, Advances in Nutrition, 2013.

Angeliki Zafeiri

Pharmacist, NKUA