Thanks so much, Surabhi!

As to your question, I’m pretty sure your body is creating ATP at all times and that includes night time. Remember that it takes several hours to digest food. So when you’ve had dinner and then go to bed, you’re breaking that dinner down throughout the night. So while you’re asleep, you still have glucose from food available to be broken down into ATP even though you’re not eating.

Moreover, even if you hadn’t eaten anything for a while, your body is still able to create ATP. In that case your body simply uses stored resources to create its ATP. For instance, although I didn’t mention it in the article, your body is also able to create ATP from protein, fat, and glycogen (long chains of glucose that your body stores in muscles).

But it’s an excellent question whether there are still adenosine molecules attached to the receptors when you wake up. I’m not entirely sure, but I think you’re right: when you wake up, you probably still have some adenosine molecules within the receptors and when you drink your morning coffee, the caffeine displaces these remaining ones, thus helping you become more alert.

Thanks again for the great question and for reading!