Final answer:
During exercise, the Bohr effect occurs, which promotes oxygen dissociation from hemoglobin to be delivered to the muscles. The increased breathing rate also helps bring in more oxygen. Endurance athletes may use substances like EPO and hGH to enhance oxygen availability to muscles.
Step-by-step explanation:
During exercise, several mechanisms occur to help get more oxygen to the muscles. One of these mechanisms is the Bohr effect. The Bohr effect is a phenomenon that arises from the relationship between pH and oxygen's affinity for hemoglobin. A lower, more acidic pH promotes oxygen dissociation from hemoglobin, allowing it to be released to the muscles. This helps increase the amount of oxygen available for muscle contraction during exercise.
Another factor that influences oxygen delivery to the muscles during exercise is the increased breathing rate. Intense muscle activity stimulates an increase in ventilation, which leads to an increase in oxygen intake. This helps to ensure that enough oxygen is available to meet the increased demand of the active muscles.
Additionally, endurance athletes may use substances like erythropoietin (EPO) and human growth hormone (hGH) to boost the availability of oxygen to muscles and improve aerobic respiration. EPO stimulates the production of red blood cells, which carry extra oxygen to the muscles. hGH promotes muscle healing and recovery, allowing for sustained high-level performance.