I'm curious. what symptoms go along with lack of oxygen?

Breathlees, confused: Symptoms depend on the speed at which it happens. A sudden drop in oxygen causes anxiety, breathlessness. A more gradual onset allows the body to adjust and symptoms include fatigue, shortness of breath with exertion, sometimes swelling of the legs.

Many: Depending on whether it is acute or chronic. When chronic, there is fatigue, breathlessness on exertion and, if carbon dioxide levels are also rising, somnolence deteriorating to coma. When acute, there is confusion (think of pilots above 10, 000 feet without oxygen), cyanosis, breathlessness progressing to frank air hunger. If coronary disease is present, there is angina.