Anecdote: For most of his adult life, my grandfather, a now-retired apple farmer, slept 5-6 hours a night, but supplemented this with 20 minute naps after lunch (which was a huge hot meal) and dinner (which was more like a lunch). Never have I seen him as exhausted as I am after my 3rd cup of coffee and 8 hours of sleep a night. And I have a desk job!
Who the heck can sleep for just 20 minutes? Do certain people have a little "sleep now" button they can press?