@zach, I think this was not what @Leonardo wanted to know.
As I understand it, he is talking about the blue onboard LED connected to D7.
And answering this - although this is not the topic of this thread ;-): “No, there is no way to do this during deep sleep - but there is also no need to switch it off during deep sleep, since it gets switched off anyhow at the very moment the Core enters deep sleep (unless of course, you added some external circuitry that keeps it lit independent of the Cores state ;-))”