Yawning

[Norfolkdan]

Just sitting here thinking, why do we yawn when we're tired?

 

I'm sure someone on here will have a decent answer...

 

[Alan Fawcett]

A few useless facts for you Dan

 

The average duration of a yawn is about 6 seconds.

 

In humans, the earliest occurrence of a yawn happens at about 11 weeks after conception - that's BEFORE the baby is born!

Yawns become contagious to people between the first and second years of life.

 

A part of the brain that plays an important role in yawning is the hypothalamus. Research has shown that some neurotransmitters (for example, dopamine, excitatory amino acids, nitric oxide) and neuropeptides increase yawning if injected into the hypothalamus of animals.

 

Many people assume that we yawn because our bodies are trying to get rid of extra carbon dioxide and to take in more oxygen. This may make some sense. According to this theory, when people are bored or tired, they breathe more slowly. As breathing slows down, less oxygen makes it to the lungs. As carbon dioxide builds up in the blood, a message to the brain results in signals back to the lungs saying, "Take a deep breath," and a yawn is produced.

 

 

So, the question remains - why do we yawn? Doctors suggest that perhaps yawning is like stretching.

 

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.

Edited July 10, 2006 by Alan Fawcett

[Guest Jan of the 2 Ghillies]

Trogg, reading your post just made me yawn....

[Alan Fawcett]

LOL its funny you should say that Jan....the page i took it from said

 

"have a pen and paper ready to write down how many times you yawn while reading this!!"

[DavyR]

Can't say I've ever noticed this:

 

"Another puzzling phenomenon is that some male animals, men included, yawn in association with penile erection (although it’s presumptuous to assume they’re bored with their sex lives)."

 

http://msnbc.msn.com/id/3076713/

 

I remember reading a theory that infectious yawning between group members originated when humans were cave dwellers, and the leader of the group would yawn to indicate that it was time to retire for the night. The other members of the group would then "yawn in sympathy" to show that they'd taken the hint.

 

Probably rubbish - I've never found that to work with guests who stay too late...

[Sportsman]

Can't say I've ever noticed this:

 

"Another puzzling phenomenon is that some male animals, men included, yawn in association with penile erection (although it’s presumptuous to assume they’re bored with their sex lives)."

 

Thats not a yawn, thats just the skin tightening

[Sharkbyte]

I was told a yawn is an eighth of an orgasm but without the mess.

 

I've yawned twice whilst reading this, I'll need to read a catch report from East Anglia to achieve the remaining six and then fall asleep.

[Steve Coppolo]

It's supposed to be a way of getting more oxygen into the lungs. No doubt to overcome the tiredness we feel at the time.

 

Who cares anyway?

 

I like the orgasm theory best though.