I'm going to read a book until I feel sleepy.

I did not have a full night of sleep and felt very sleepy the next day.

Do these activities in another room until you feel sleepy.

After a while, you will begin to feel very sleepy.

And they're more likely to feel sleepy during the day.

Don't go back to bed until you begin to feel sleepy.

About half an hour later you will feel sleepy again.

Without enough sleep, you may feel sleepy during the day.

Get up and work or read until you do feel sleepy.

She asked him if he felt sleepy but got no response.