Why do people yawn ?
There are a several theories about yawning and why people yawn. While medical personnel and researchers have a good idea about the cause, some of the story on yawning remains a mystery. Most people understand that human beings yawn when they are tired and need to rest. But we also yawn after we wake up in the morning. Research has asked the question: Is there a connection between night yawning and morning yawns? The one absolute truth about yawning is that it’s not a voluntary action. Animals, including humans, yawn involuntarily. Some people believe that we yawn because of a low level of oxygen in the blood.This theory indicates that a yawn causes us to inhale a large amount of air to replenish the oxygen. But research shows that people don’t yawn in response to all low-oxygen levels in the blood (hypoxia). Apparently we yawn when we are tired and blood oxygen is low but not in other hypoxia situations (such as activity at high-altitudes). Other Theories About Yawning Include: • Peopl
