Our myoglobin simply has too high of an affinity for oxygen and it will not be able to successfully unload enough oxygen to the resting tissue or to our exercising tissue. And that's exactly why it's myoglobin that is used as the storage protein that stores oxygen inside our muscle cells. But it's the hemoglobin that is used as the carrier, because it binds oxygen in a non cooperative fashion, which gives it a sigmoidal shape and it is able to successfully unload enough oxygen to the tissues of our body. So once again, we see that hemoglobin's cooperative behavior allows it to unload much more oxygen successfully to the tissues than myoglobin. And this is why our body prefers to use hemoglobin as a transporter for oxygen inside our cardiovascular system, inside our bloodstream. And myoglobin simply has too high of an attraction to oxygen.