Tell me why we yawn?
Yawing can be contagious.
Just thinking and reading about yawing makes us yawn. It may surprise us but,
apart from babies, kids, teenagers, adults; even some birds, reptiles and most
mammals also yawn.
However, the reason why we
yawn is a bit of a mystery, though many people presume that humans yawn because
our bodies are trying to take in more oxygen and get rid of extra carbon
dioxide. There is also very little research about yawning because it is not a
problem for most people.
Did you know these facts on yawning?
- The earliest occurrence of yawn happens in humans at about 11 weeks after conception (i.e., before the baby is born)
- Average duration of a yawn is approximately 6 seconds
- A part of the brain that plays an important role in yawning is the hypothalamus ( Research shows that some neurotransmitters and neuro-peptides increase yawning if injected into hypothalamus of animals)
- Yawns become contagious to people between first and second years of life
For most who believe,
human yawn because they need more oxygen and try to get rid of extra carbon
dioxide, the theory makes some sense. According to this hypothesis, when people
are tired or bored, they breathe more slowly and as breathing slow down, less
oxygen makes it to the lungs. This builds up carbon dioxide in the blood, a
message is sent to the brain, which signals back to the lungs to take a deep
breath,” and a yawn is produced.
Did you know? You yawn
when you are bored. Scientists confirmed this observation by comparing the number
of yawns in some students ( in their late teens) who watched interesting music
videos to the number of yawns in students who watched an uninteresting TV
programme. As expected, people who watched uninteresting TV programme yawned
more ( 5-6 yawns in half hour) than those who watched interesting videos (3-4
yawns in half hour).
Yawning and stretching
increase blood pressure and heart rate and also flex muscles and joints.
Evidence that yawning and stretching may be related comes from the observation
that if you try to stifle or prevent a yawn by clenching your jaws shut, the
yawn is somewhat “unsatisfying”. For some reason, the stretching of jaw and
face muscles is necessary for a good yawn.