Hemoglobin is an iron-containing protein in red blood cells that transports oxygen throughout the body. The transport of oxygen by hemoglobin is an example of chemical bonding. Hemoglobin levels impact the ability to climb Mount Everest due to decreasing oxygen levels at high altitudes. Blood doping procedures like EPO injections and blood transfusions aim to increase red blood cell counts and oxygen delivery to muscles, giving athletes a competitive advantage, though they can have serious health risks.