Final answer:
Endurance athletes may use substances like EPO and hGH to boost oxygen availability and recovery for improved aerobic sports performance, along with caffeine which increases endurance and fat oxidation.
Step-by-step explanation:
To enhance aerobic athletic performance, endurance athletes use various ergogenic aids. One common practice is increasing oxygen availability to muscles to boost aerobic respiration. Substances like erythropoietin (EPO) and human growth hormone (hGH) are used for these purposes. EPO, which is naturally produced by the kidneys, stimulates the production of red blood cells, thereby increasing the oxygen that can be delivered to muscles during exercise. On the other hand, hGH supports muscle and tissue healing post-exercise, allowing for faster recovery and the ability to sustain high-level performances. Additionally, athletes consume caffeine, which is also a proven ergogenic aid enhancing aerobic activities such as running, cycling, and other endurance sports by improving performance and increasing fat oxidation.