29/05/2026
If you are a female runner, athlete, or trying to lose weight through exercise β your trainer probably missed the single most important number in your blood. π©Έ
We see it every week. Women who train hard, push their bodies relentlessly, and still donβt see results. They get tired faster. Injuries pile up. Performance plateaus. And the conclusion is usually wrong β they blame technique, hormones, age or genetics.
The real problem? Their hemoglobin is too low.
Up to 35% of female athletes β and 52% of adolescent female athletes β have iron deficiency, and many run with hemoglobin below 12 g/dL without realising the cost they are paying. Many women have come to accept single-digit hemoglobin as normal because it does not disturb their daily routine. That perception is dangerous β and it is why your effort isnβt translating to results.
Here is the science nobody explains.
When you exercise, your muscles need fuel and oxygen. Fuel comes from inside the body. But oxygen comes from the air around you β and it is in gas form. Your blood is liquid. So how does gas get into liquid? Hemoglobin. The protein in your red blood cells that captures oxygen and carries it dissolved in your bloodstream to every working muscle.
Research is now unequivocal β a 1 g/dL drop in hemoglobin reduces your VOβ max by approximately 5%. A 2 g/dL drop reduces your leg oxygen uptake at maximum exercise by nearly 18%.
Translation in plain English β if you are running at 6 km/h speed but your hemoglobin is low, your body is internally working at 8 km/h to keep you going. Two identical vehicles running at the same speed β but one of them has its engine roaring at twice the load.
That is why you are tired. That is why you are not recovering. That is why injuries are mounting.
Fix your hemoglobin first. Keep it above 12 g/dL β ideally 13. Then everything else you do in training will work.
Run with Science. π