I tend to yawn all the time. And get this, when I am tired or something, I will honestly just sit back and do some stretching to yawn on purpose for 15 minutes straight. Because for some reason I've been noticing after yawning for that long, I get back a lot of energy! Why is this?

All inputs appreciated thank you!

No one knows exactly why we yawn but it is supposed, by some, that it is a way to get more oxygen to the body. You somewhat prove the point by saying that you "get back a lot of energy"