Due to the fatigue associated with having this illness, I often don't have sufficient energy to even muster up a chuckle when I find something amusing. However when I do laugh, I often find myself having improved energy for around the next 10 minutes or so until it wears off. I also notice I don't yawn or feel the urge to yawn as often as I normally do. In an odd way, it almost feels as if I am getting more nutrient rich blood to my brain. Can anyone explain this to me?