There is a need for a comprehensive set of exercise stress markers and micronutrient status markers for monitoring training load and nutritional status in athletes.
Athletes require regular exercise training to improve performance. Functional overreaching is needed to trigger the body. As a result exercise stress markers, like myokines and inflammatory factors, are released and the body adapts to the training load. When overreaching is non-functional, and recovery is postponed, this may develop into an ongoing chronic inflammation. In that case, (over)training results in infections and underperformance. Measuring the inflammatory exercise stress response could be a way to monitor training load. And adjust training programs when needed.
The (micro)nutrient status is also strongly linked to exercise training and performance. A negative energy balance impairs immunity and increases the risk of infection in athletes. This will limit training adaptation and performance. The role of micronutrients on performance and health is less clear. Relations between vitamin D and muscle function have been indicated. And also the role of iron in oxygen transport during exercise. For other micronutrients, like Magnesium, Calcium and folate, only limited information is available. A significant proportion of athletes likely suffers from iron and other micronutrient deficiencies..
Therefore, monitoring training load and assessing micronutrient status is important in sport practice. More research is needed, to establish which exercise stress markers and which micronutrients should be measured and, more specific: when to measure these stress markers and micronutrients in relation to exercise.