You may laugh at this and I have no idea if there's any medical knowledge behind this theory, but back when I was pregnant with my two daughters, I would just drag without caffeine.
And my mom would swear by taking an ice cube and running it back and forth over the inside or your wrist, until the ice cube melted.
She claims this sends blood to the brain and you'll feel alert
.
Do I believe it? Oh on some wacky level, it could work. Did I try it? I sure did! lol