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Does caffeine actually make you more tired in the long run?

I’ve heard people advise against drinking lots of strong coffee and saying it makes you tired. I thought it made you more alert and awake.
It doesn't make you more tired. But that's not to say the extent that people use it isn't a problem.

Just by way of background, adenosine is a chemical that makes you feel sleepy. You will have felt that 'pressure' to sleep. That's caused by adenosine. It builds up over the course of the day, so by the time it's time for you to sleep, you feel sleepy. When you sleep, your body clears the adenosine build up, so by the time you wake up you should feel awake. If you don't sleep enough not all of the adenosine will be cleared, which means you will feel sleepy sooner.

Caffeine is a stimulant. It does make you feel more awake. But it does that by suppressing the body's ability to detect adenosine. The adenosine is still there and is still building up, but your body doesn't know it's there. So you feel awake. Caffeine effects drop off over time, but fundamentally when it has worn off your body suddenly realises that there's a lot of adenosine there, and you feel very tired. That's a crash. It's your body going from thinking it doesn't need to sleep at all to realising that it really needs to sleep.

So caffeine doesn't make you feel more tired. What will make you feel more tired is not getting enough sleep, but then masking that in the morning or throughout the day using caffeine. The problem is not caffeine itself. It's people using caffeine as a substitute for sleep. You can then, of course, become addicted to caffeine which has its own problems. But in reality if you're getting enough sleep, you shouldn't need caffeine at all. The fact that people are so often so dependent on it is a real problem.
Original post by Crazy Jamie
It doesn't make you more tired. But that's not to say the extent that people use it isn't a problem.

Just by way of background, adenosine is a chemical that makes you feel sleepy. You will have felt that 'pressure' to sleep. That's caused by adenosine. It builds up over the course of the day, so by the time it's time for you to sleep, you feel sleepy. When you sleep, your body clears the adenosine build up, so by the time you wake up you should feel awake. If you don't sleep enough not all of the adenosine will be cleared, which means you will feel sleepy sooner.

Caffeine is a stimulant. It does make you feel more awake. But it does that by suppressing the body's ability to detect adenosine. The adenosine is still there and is still building up, but your body doesn't know it's there. So you feel awake. Caffeine effects drop off over time, but fundamentally when it has worn off your body suddenly realises that there's a lot of adenosine there, and you feel very tired. That's a crash. It's your body going from thinking it doesn't need to sleep at all to realising that it really needs to sleep.

So caffeine doesn't make you feel more tired. What will make you feel more tired is not getting enough sleep, but then masking that in the morning or throughout the day using caffeine. The problem is not caffeine itself. It's people using caffeine as a substitute for sleep. You can then, of course, become addicted to caffeine which has its own problems. But in reality if you're getting enough sleep, you shouldn't need caffeine at all. The fact that people are so often so dependent on it is a real problem.

TL;DR Caffeine blocks your adenosine receptors and makes you feel alert when you are tired.

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