Final answer:
Hypopnea is a condition characterized by shallow or slow breathing, leading to reduced oxygen levels in the blood and is associated with sleep disorders such as sleep apnea, carrying significant health risks.
Step-by-step explanation:
When hypopnea occurs, it represents a period of shallow breathing or a lower rate of breathing that leads to reduced airflow into the lungs during sleep. This may result in an abnormally low concentration of oxygen in the blood, known as hypoxemia. Hypopnea is often related to sleep disorders, such as sleep apnea, where breathing stops and starts repeatedly during sleep. It's important to note that hypopnea is associated with significant health risks, including the potential for stroke, heart failure, and chronic tiredness. Unlike during exercise, where an increase in breathing (hyperpnea) happens in response to muscle demand for oxygen, hypopnea can adversely affect the body by impeding proper respiratory function and gas exchange.