The document discusses magnesium needs for athletes. It notes that athletes have higher magnesium requirements than non-athletes, between 400-800mg daily, as magnesium plays an important role in energy production, nervous system function, lactic acid removal, and replacing what is lost through sweat during exercise. A magnesium deficiency can impair immune function and increase susceptibility to infection in athletes. The document recommends magnesium supplementation for athletes, especially endurance athletes, to improve cellular metabolism, cardiorespiratory function, and magnesium stores.