A Mighty Mineral

If you run out of steam during regular workouts, you could be in need of an important mineral.

Fatigue during workouts could have many underlying causes. Recent research suggests a lack of zinc could be one factor. When 14 men were fed either a low-zinc or zinc-supplemented diet for 9 weeks, the men on the zinc diet performed much better on exercise tests compared to the men on the low-zinc diet.

Aim for at least 12 milligrams (mg) of zinc per day from food and supplements. However, zinc can be harmful in excessive amounts, so avoid getting more than 30 mg per day. Zinc helps rid the body of excess carbon dioxide that builds up during a workout, so if you're low you may tire more quickly. It also facilitates oxygen uptake, carbon dioxide output, and other metabolic processes that help maintain stamina. Zinc performs a variety of other functions in the body, as well, including aiding in the synthesis of genetic material, maintaining a healthy immune system, speeding wound healing, and helping enzymes perform their various functions.

Low dietary zinc decreases erythrocyte carbonic anhydrase activities and impairs cardiorespiratory function in men during exercise. Lukaski, H. C., The American Journal of Clinical Nutrition 2005 May;81(5):1045-1051.