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The reason why you are tired or even more tired after drinking coffee? how long should you pay attention to how long should you drink coffee in advance?

Published: 2026-08-22 Author: World Gafei

Last Updated: 2026/08/22, Coffee contains caffeine, which blocks sleep-promoting factors in the body. The study points out that drowsiness is related to a molecule called adenosine, which tells the brain that the body is tired, sleepy, and it's time to rest. "caffeine" and "adenosine" have similar chemical structures, so they are drinking.

Coffee contains caffeine, which blocks sleep-promoting factors in the body.

The study points out that drowsiness is related to a molecule called adenosine, which tells the brain that the body is tired, sleepy, and it's time to rest. "caffeine" and "adenosine" have a similar chemical structure, so after drinking coffee, "caffeine" becomes real. When pseudoadenosine (caffeine) binds to adenosine receptors in the brain, people become more excited and awake. At this time, the brain does not receive signals of physical fatigue or drowsiness from the real "adenosine".

But not all people are excited and awake after drinking coffee. Especially when feeling very tired, many people will choose to drink coffee to refresh themselves, but not all people will be excited and awake after drinking coffee. For example, some people will be hypnotized or even show signs of "more tired" after drinking coffee. There are mainly the following reasons for this signal: excessive coffee consumption itself does not make people feel tired, but the caffeine in coffee sometimes sends a signal of fatigue to the body, such as the more common excessive intake of caffeine. many studies have pointed out that drinking coffee is good for human health, but excessive coffee is counterproductive. Excessive coffee consumption is easy to stimulate the intestinal tract and mucous membrane of the human body. It is recommended that adults consume no more than 400 milligrams of caffeine a day.

Coffee drinking time is recommended after breakfast and lunch (it is not suitable to drink coffee on an empty stomach), drinking too much coffee in the evening will affect sleep quality, long-term lack of sleep will lead to cognitive impairment, immunity decline, and so on.

Usually after drinking a cup of coffee in the afternoon, the coffee will stay for a period of time after entering the gastrointestinal tract, during which the small intestine absorbs caffeine and spreads it to all parts of the body. after 20 minutes, caffeine begins to reach the brain to bind to adenosine receptors. When caffeine doesn't work, if you're already sleepy, you might as well sleep for 20 minutes (you'll be more tired after more than 30 minutes of deep sleep). People who drink coffee for a long time have a high tolerance to caffeine because caffeine blocks adenosine receptors and the body produces more adenosine receptors to counteract the effects of frequent caffeine intake. at this time, a cup of coffee can no longer cheer you up as it used to be, so if you are already sleepy and drinking coffee can no longer achieve the refreshing effect, it is better to get some sleep. One's own constitution is not suitable for drinking coffee.

Such as adverse reactions to coffee; people with a history of anxiety or panic; pregnant and lactating women; patients with gastritis and gastric ulcers; patients with liver disease, and so on.

Last. Although drinking coffee can be refreshing, but drinking coffee can not replace sleep and can not make up for lack of sleep, caffeine is only a short-term solution, can not really eliminate fatigue. All in all, everyone's reaction to coffee is different. Drinking a moderate amount of coffee can refresh us, but getting a good night's sleep is also important. If you don't get enough sleep, any more refreshing methods are in vain. ~ * Photo source: for more information about coffee beans on the Internet, please follow the coffee workshop (Wechat official account cafe_style) professional coffee knowledge exchange please add Wechat kaixinguoguo0925

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