Point. I read the sleep deprivation meaning into the phrase "pressure caused by the operational tempo, something the RN and USN would recognise" - because I'm somewhat familiar with the subject.

Try a search on "naval officer sleep deprivation", and notice just how many military, government, and adjacent sites have been talking about that specific problem. (For me, its role in accidents and collisions pops up in the 2nd sentence of Google's AI overview.)