The Dietary Reference Intakes (DRIs) are a set of recommendations for healthy persons. For the most part, recommendations are determined experimentally under controlled conditions of light activity. During increased physical activity, it is expected that micronutrient requirements would increase relative to the inactive state. Micronutrients of interest to athletes are those associated with oxygen handling and delivery, such as iron, and vitamin D, a newly emerging function of which is to maintain muscle strength. The DRI report on electrolytes (including water) is the most recent set of recommendations. In addition to recommendations for intakes to meet needs, many micronutrients have an upper level that indicates caution in consuming a large amount. We illustrate the process of setting DRI values for the micronutrients (including electrolytes and water), and provide a summary of instances where physical activity needs were considered when DRI values were derived. Understanding the origin of DRI values for micronutrients will assist in understanding how to use the values in assessment and planning.