"Are you getting in enough red meat? Is your ferritin level at least 50-60? If you dont know what your ferritin level is get it checked NOW."
Numbers can freak people out so I feel I should at least offer a response to this. I'm not a coach, like the person who wrote this, but I've read a lot about ferritin because my daughter's performances were suffering and she was found to have very low ferritin levels.
From what I've read, ferritin is the important number to check when your iron is measured. The doctor has to specifically order that it be measured when a blood test is done. Iron helps in delivering oxygen to muscles--very important!
The range for a "normal" person (not a runner) is 15 to 77, or thereabouts. In what I've read, there are two camps. One says a runner's level should be 50 or above. The other says 30 or above. In either case, you see that it should be significantly higher than the minimum.
Iron levels are important and you can learn about them by talking with your doctor (although doctors who don't know about running might not be helpful) and your coach (who might or might not know about these things), and by reading and thinking about posts like the coach's, mine, and others that seem reputable.