They can be, but that's if Windows decides to move a portion of SQL's memory into the page file (memory pressure and SQL not releasing memory when requested). It isn't something that will affect PLE, which is a SQL measurement and solely related to SQL's internal memory management.

I'd personally ignore PLE during CheckDB execution. Because it reads the entire database and because it marks pages brought in as 'disfavoured', meaning they'll be the first to be thrown out of cache when space is needed, PLE will be low, it's kinda expected.

Now, if PLE is dropping that badly during normal operation when CheckDB isn't running, you may well have a problem of too much data being read. It doesn't mean you have an IO contention problem, it means you're reading more data into memory than memory can handle. The fix is more memory, optimise queries or both.