Final answer:
Krakauer experiences symptoms of hypoxia when he goes without supplemental oxygen, including fatigue, headaches, and confusion. Extreme anxiety and confusion are commonly reported symptoms.
Step-by-step explanation:
When Krakauer goes without supplemental oxygen for some time, he experiences symptoms of hypoxia, which include fatigue, headaches, and confusion. These symptoms are a result of the body not receiving enough oxygen to maintain energy homeostasis. It is important to note that everyone may experience these symptoms differently, and some individuals may also experience a sense of euphoria. However, extreme anxiety and confusion are more commonly reported symptoms.