What condition occurs in the body when a person suffers from hypoxia?

Hypoxia is a condition characterized by a deficiency of oxygen in the tissues of the body. When a person suffers from hypoxia, it means that the cells and organs are not receiving an adequate supply of oxygen to function properly. Oxygen is essential for the production of energy within cells; without it, metabolic processes can become impaired, leading to symptoms such as fatigue, confusion, and even loss of consciousness if the condition becomes severe.

While increased carbon dioxide in the blood can be a result of various respiratory issues, it is not a defining characteristic of hypoxia itself. High altitude sickness may occur due to reduced oxygen availability at higher elevations but is not synonymous with hypoxia and is a specific condition with additional factors involved. A rapid heartbeat, or tachycardia, can be a symptom of hypoxia as the body tries to compensate for low oxygen levels, but it is not the condition itself. Understanding the primary issue of insufficient oxygen supply helps clarify why the correct answer identifies the lack of oxygen in body tissues as the essence of hypoxia.