There isn’t a great deal of direct data on what kind of impact low intake of vitamins/minerals has on exercise performance or capacity. That may be because active individuals often do take recommended doses of vitamins/ minerals. However, taking less-than recommended dosages does lead to apparent functional impairments. For example, a “severe deprivation of folate and vitamin B12” leads to anemia and low endurance work performance. An iron deficiency negatively impacts muscle function and, subsequently, restricts work capacity. Similarly, a magnesium deficiency demands greater oxygen needs to perform “submaximal” exercise and actually reduces endurance. It also should be noted that vitamin D has been considered a “sleeper nutrient.” Per growing research, the vitamin plays a key role in many bodily functions and is overlooked as a factor in athletic performance.