Longer naps provide greater and more sustained benefits but increase the risk of sleep inertia.

“now that's not to say that when you sleep or you nap longer you don't start to get more benefits you do and those benefits are both greater in their magnitude and sustain for a longer period of time they do it's just that you have to understand the tradeoff that you will suffer which is I will get more bang for my book and I will get more benefits but I will in the first sort of hour or so have to understand that at that point I may even be functioning worse than than that which I did before I even started napping”