Is this not clear from the term?
"I'm going to go take a nap in bed."
vs
"I fell asleep in a chair."
"I'm going to go take a nap in bed."
vs
"I fell asleep in a chair."
In medicine, sometimes semantics are more important than you think.
> Among nappers, we further defined napping intention based on the question “In general, were these naps planned, or did you fall asleep without meaning to?” Nappers who answered “naps planned” were classified as intentional nappers, and those who answered “fell asleep without meaning to” or “both (some planned/some not)” were classified as unintentional nappers.