[Lewis Thomson (OP)]

Brian wishes to know the answer to this question.

"Why does coffee make me sleepy? I generally find that coffee does not affect my ability to sleep; if anything, it is more likely to get me to sleep faster; as a few times I have taken it to try and stay awake but have promptly dropped off half an hour or so after my cup. A couple of friends have reported the same, so I was wondering; have we simply gotten used to it? (I typically have one cup a day - closer to the evening than the morning) or is something else going on?"

Leave your thoughts in the comments below...

[FannieMaloy]

I know it sucks, but take a break for a few weeks from caffeine, or wean yourself off of it a bit, then come back to it.

[wolfekeeper]

No, that's to be expected. Coffee doesn't so much wake you up, it's not a simple stimulant, it's more of a preventative for getting tired.

As I understand it, coffee contains caffeine, which has a half life of about six hours in the body, and which loosely fits into adenosine receptors in the brain. The caffeine enters them, hangs about there for a while before falling out. It blocks adenosine from getting into them while its there.

Normally, adenosine, during the day, is produced in the body, and fits into the receptors where it sticks quite snugly. When the receptors get full enough, you'll tend to get sleepy and fall asleep. While you're asleep, while adenosine will still be produced, the receptors are getting emptied out faster than they are filled, and when the adenosine levels are low enough, you'll wake up.

But if you drink caffeine during the day, particularly the morning, the caffeine will slot into the receptors and stop them filling. That way you will still be more alert later in the day because more of the receptors will be empty. So it stops you feeling tired. And later at night, you'll not be as tired, and may well take longer to fall asleep particularly if you had a lot of caffeine.

But if you have coffee late in the evening, the effects are sort of reversed. The receptors will already be mostly filled up during the day, and they'll continue to fill with caffeine in your system, but more slowly. So it won't make much difference at the end of the day, you'll get tired and fall asleep at about the same time.

However if you have caffeine in your system while you're asleep, the removal will happen at the same rate, but any additional adenosine produced while you are asleep will have a hard time getting into any receptors because it will get blocked by caffeine. So overall you'll be clearing the adenosine much faster and you'll wake up earlier the next day.

So basically, what I'm saying is, coffee doesn't normally make you sleepy, you're probably drinking it when you were already getting sleepy. Caffeine mostly acts over several hours, rather than having short term effects.

However, this model is doubtless an oversimplification, coffee isn't just caffeine, it is a complex witches brew of chemicals, and some short term effects are often seen.

[evan_au]

The other aspect of coffee-drinking is how long it takes to get into your system.
I've heard that it can take 20 minutes on an empty stomach; presumably, if you drink it after food, it will take longer to be absorbed.

[wolfekeeper]

Probably somewhat, but liquids tend to fall to the bottom of the stomach and siphon off first, so I wouldn't expect it to make a lot of difference.

[Rocky6419]

Hi everyone;

We all love to drink a cup of coffee in the morning or in the evening to stay active and fit. We drink coffee too far away from our stress and start our day with a fresh mood to work effectively.

Can you know that coffee contains caffeine, it can be absorbed into our body within 50-60 minutes. When caffeine grinds away, the molecules bind with the receptors which can cause us to be sleepy. But when we drink 4-5 cups of coffee in a day it can contain a lot of caffeine which consumes more time to absorb and you stay awake more time but drinking coffee above 3-4 cups in a day can not be good for your health.
 
To get more brief information about why coffee makes me sleepy click here.https://coffeeaim.com/health-benefits-and-disadvantages-of-coffee/ [nofollow][/ftp].