Final answer:
Training at altitude enhances performance by increasing hemoglobin levels and the release of oxygen to tissues, due to acclimatization. These benefits continue upon returning to sea level, offering a temporary performance boost. However, risks like altitude sickness necessitate careful acclimatization.
Step-by-step explanation:
Training at altitude is beneficial for performance both at altitude and upon returning to sea level due to physiological adaptations. When exposed to high altitudes, where atmospheric pressure is lower and oxygen partial pressure decreases, our body undergoes a process called acclimatization. Acclimatization involves an increase in the production of hemoglobin, allowing the blood to carry more oxygen to compensate for the lower oxygen saturation in the air. Additionally, there is an increase in the concentration of 2,3-bisphosphoglycerate (BPG) in red blood cells, which facilitates the release of oxygen from hemoglobin, making it more available to body tissues — a crucial adaptation when oxygen is scarce.
Upon returning to sea level where atmospheric pressure is higher, these adaptations lead to enhanced performance due to an increased oxygen-carrying capacity of the blood and a more efficient release of oxygen to the muscles. The body retains these adaptations for a certain period, thus providing an advantage in sports and physical exertions. However, exposure to altitude also comes with risks such as altitude sickness, characterized by symptoms like headaches and nausea, which is why gradual acclimatization is important for anyone considering altitude training.