Is there a scientific explanation for why we get punchy when we're real tired?

[raccoon]

Inquiring minds want to know....

[TZ]

1. define punchy.....

Muscle fatigue is do to lactic acid build up. Lack of sleep affects the brain chemistry in such a way that you feel "tired"
http://en.wikipedia.org/wiki/Sleep_deprivation#Effects_on_the_brain
Basically neurotransmitters control the feeling of being alert. I believe thats the answer you are looking for.

[raccoon]

2. Punchy = giggly, giggling an awful lot over something that really isn't THAT funny.

Or may not be funny at all.

[TZ]

3. yeah its neurochemistry.

Basically lack of sleep can mimic being drunk or high sometimes, if you are tired enough.

[RandomThoughts]

4. .

.

[Deep13]

5. WHAT THE HELL DO YOU MEAN BY THAT!!!!?????

Sorry. Didn't sleep well. :evilgrin:

[IcyPeas]

6. David Letterman....

I find if I watch Letterman at night when it is on it's hilarious. However, if I record it and watch it during the day I never find it as funny.

[BlueIris]

7. Good question. I get *really* punchy when I'm tired.

Like, make friends with people I wouldn't even look at in other situations kinda punchy. And lemme tell you about the time I was once awake for 49 hours. That got UGLY.