About nine percent of women suffer from an iron deficiency, according to the most recent stats from the Centers for Disease Control and Prevention—but that number`s even higher for physically active women, say experts, Fox News reports. How can you tell if your levels are a little low? Be on the lookout for these warning signs.

Fatigue

“The body uses iron to make hemoglobin, the substance in red blood cells that carries oxygen,” said Blaire Morriss, a nurse practitioner at the Vanderbilt Center for Integrative Health. When you don`t have enough healthy blood cells, you start to feel exhausted.

Difficulty Focusing

Neurotransmitter synthesis may be altered in people with an iron deficiency, leading to lower-than-normal functionality, Morriss said.

Apathy

Another byproduct of that altered neurotransmitter synthesis.

Breathlessness

Without enough iron in the blood, the body becomes starved for oxygen.

Unusually Pale Skin

A washed-out appearance can be caused by reduced blood flow and decreased number of red blood cells.

Trouble Doing Your Normal Workout

Low iron levels can cause your endurance to suffer, according to a recent Cornell study.

Brittle Nails

Thin, frail fingernails and toenails are another way to tip you off to a possible iron deficiency.

Pink or Red Urine

This can occur in people with an iron deficiency and is caused by increased intestinal absorption of certain pigments.

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