ive heard it might have somethign to do with breathing, or not breathing enough, but why do we only do it when we're tired? WHAT IS IT?!?!
2006-11-06 13:57:05 · 4 answers · asked by Anonymous in Health ➔ Diseases & Conditions ➔ Respiratory Diseases
lack of oxygen in the brain. it's a signal that you're mind and body are tired and you need to sleep to recharge.
2006-11-06 16:00:50 · answer #1 · answered by Kria 3 · 0⤊ 0⤋
When you are tired, bored, or concentrating, you tend to take shallow breaths. A yawn is signaled by your brain because it is not getting enough oxygen.
2006-11-06 15:07:48 · answer #2 · answered by twirlersmom 3 · 0⤊ 0⤋
It's from lack of oxygen
2006-11-06 15:11:58 · answer #3 · answered by Kylie 6 · 0⤊ 0⤋
Where you are really tired and you almost dislocate your jaw. T_T
2006-11-06 13:59:26 · answer #4 · answered by Red Panda 6 · 0⤊ 0⤋