Endurance Athletes Have an Increased Risk for Iron Deficiency—Here's You Need to Know Kelly Pritchett It’s common to associate a poor performance with low iron.“ I had a bad race, maybe I should check my iron?”“I’m feeling fatigued during workouts—could it be my iron levels?” I get these questions from the athletes I work with a lot. And while there are countless variables that can contribute to poor performances or fatigue, one thing we do know is that iron is important for runners. If your iron levels are low and you don’t do anything about it, you will eventually feel the negative impact on performance. Here’s what you need to know about both iron and ferritin levels.