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coffee_frog
· 50 weeks ago
· FIRST
I found that if you're dead tired, coffee does little to wake you up, blasphemous though it may sound.
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deleted
· 50 weeks ago
Coffee helps you to stay awake by blocking the adenosine receptors in your brain. Your brain produces more and more adenosine while you're awake, and the more receptors are triggered by it, the more you're experiencing the typical feeling of drowsiness, if caffeine blocks them, this effect is reduced. So coffee isn't actually making you more awake, it rather makes you less tired (as opposed to "real" stimulants). If you're drinking coffee on a regular base, your brain will form more of those receptors, so the effect is likely to diminish. And you can only push the doses so far to retain the effect. If you reach a certain, individual level, even very high doses won't do a lot, while side effects remain.
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deleted
· 50 weeks ago
/2 It is different with older people sometimes. Many elderly persons have trouble falling asleep, even though they feel very tired, which in many cases is caused by a reduced blood circulation in their brains. One very fast, short term effect of caffeine is to increase the blood circulation in general, while the caffeine takes 15-20 minutes to start docking to the adenosine receptors. So the trick is to drink a coffee and go straight to bed and (hopefully) fall asleep before the caffeine starts blocking those receptors. This can make sense if you a) usually fall asleep quite fast once you lay down and b) you're frequently drinking coffee anyway, so you're a bit immune to the adenosine thing.
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