Choose the correct word to complete the doctor's recommendation.

"You need to ___ at least 8 hours of sleep every night for optimal health."

The correct answer is get.

We "get sleep" - this is the most natural collocation when talking about obtaining the right amount of sleep for health. "Take" is used with medicine or breaks, "make" suggests creating something, and "catch" refers to brief naps or sleep when tired, not regular nightly sleep duration.