What is the cause and effect of how lack of oxygen is related to lack of energy?

Lack of oxygen leads to insufficient aerobic respiration, which is the primary process through which cells generate energy in the form of ATP. When oxygen levels are low, cells switch to anaerobic respiration, producing less energy and generating lactic acid as a byproduct. This reduction in energy availability can result in fatigue, impaired physical performance, and diminished organ function, ultimately affecting overall health and well-being. In summary, inadequate oxygen supply directly hampers energy production, leading to various physiological challenges.