It appears they've changed the reference range for ferritin levels. The Normal Range is between 80-300. So I am considered to be in the "depleted iron stores" category at 26. I once got my ferritin up to 50 and I remember I did feel somewhat better when I was out walking. I don't have low ferritin symptoms such as feeling out of breath or dizziness, so I'm thinking getting to optimal levels over 80 is a lot!