Read the following context and answer the question.
Context: Over the last year or two , I found myself even sleepier : spending entire weekend days asleep , and ultimately not feeling refreshed . Something was wrong . I went to my doctor , who did a bunch of blood tests and ultimately referred me to the Sleep Disorders Program at a local medical institution .
Question: What may be the reason for their visit to the doctor ?
Answer:


They have been excessively sleeping .