"I kept sleeping" or "I kept asleep"

Question

I kept sleeping.

or

I kept asleep.

Which is correct? I have gotten different opinions.

Answer 1

"Keep" in this sense, when used without an object, is usually followed by a verb. ("Sleeping" is the present participle, not the gerund, here.) So

I kept sleeping"

is preferred.

The exception is adjectives of position, so "I kept away" "I kept close" is fine too.

With other adjectives "stayed" is preferred over "kept".

I stayed asleep

is also good.

When used with an object "kept" is good.

I kept him asleep.

Answer 2

As you have confirmed that you mean "I continued to sleep" what you should say is "I kept on sleeping" or "I stayed asleep". Neither of the options you suggested is normal English.

Answer 3

kept sleeping is the proper way here.

Saying asleep is mentioning that you are currently sleeping. Doesn't match with proper english grammar.

Answer 4

Interesting question. When describing an activity or state, I think it matters whether "keep" implies maintaining the activity/state on purpose, or merely means the activity/state is continuing on its own.

If there is a conscious decision or exertion of effort, an adjective is OK: I barely managed to keep awake through the boring presentation; I kept quiet. But *keep asleep is weird because you are not purposefully staying asleep.

As others have noted, with an object there is causation, and an adjective is OK because the subject is making an effort: I kept him asleep.

If the subject of the sentence is inanimate and thus unable to act, an adjective does not work: *the prices kept high.

The present participle is always OK: I kept sleeping; The prices kept rising.

Note that there are many senses of "keep" and they may have different grammatical constraints.

Answer 5

TL;DR: "I kept asleep" is not grammatical or idiomatic English. "I kept sleeping" is correct.

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The verb "keep" has many different uses that require different kinds of grammar (and, in fact, often the grammatical context is what allows you to tell which sense of "keep" is intended).

The sense relevant to your question, meaning "to continue or repeat an action", always takes a verb in the -ing form (i.e. a present participle) as a complement:

"I kept walking." (= "I continued to walk.")
"He keeps coming back." (= "He has come back several times, and will likely come back again.")
"I kept waking up." (= "I woke up several times.")
"We will keep trying." (= "We have tried before, and we will try again.")

There is a related sense, meaning "to remain in a state", that takes an adjective instead, as in:

"I kept quiet." (= "I stayed quiet." / "I did not say anything.")
"We kept away from them." (= "We avoided them." / "We did not go near them.")
"Keep strong!" (= "Remain strong!" / "Do not give up!")

However, that particular sense of "keep" is normally used only in with a limited number of adjectives that typically relate to to active avoidance of something. When you're asleep, you don't normally do anything actively, so it does not make sense to say that you "kept asleep" — that would imply that you 1) knew you were asleep, 2) did not want to wake up, and 3) expended some mental effort to avoid waking up. This is usually not the case, so saying that you "kept asleep" is not only weird and unidiomatic — it is also arguably at least borderline ungrammatical, as "asleep" is not one of the few adjectives that can be used with "keep" in this sense.

However, you can idiomatically say:

"I kept awake."

implying that you stayed awake and actively avoided falling asleep, even though you were tired and might've fallen asleep if you didn't resist it. (On the other hand, if you had insomnia and stayed awake even though you wanted to fall asleep, then you would not usually say that you "kept awake", but merely that you "stayed" or "was" awake.)

Admittedly it's not one of the most common usages of "keep" + adjective, but it's fairly easy to find examples of it* and fluent speakers would normally recognize the usage in context without finding it in any way unusual.

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*) Well, at least it's easy if you choose your search terms carefully to avoid instances of the much more common transitive usage of "keep awake", meaning "to prevent someone from sleeping" (as in "The noise kept me awake"). Just searching for the phrase "I kept awake" works fairly well.