I found that I don't feel sleepy after lunch if I work while standing up. But if I sit in a chair I can feel sleepy and a five minute nap makes for a more produ

I found that I don't feel sleepy after lunch if I work while standing up. But if I sit in a chair I can feel sleepy and a five minute nap makes for a more productive afternoon than fighting the sleepiness. Has anyone else observed this effect of curing after lunch sleepiness by standing up?