one way degassing valve knows that coffee has the function of refreshing oneself, that's why the consumption of coffee is just preceded only by petroleum's. For most people, coffee is the drink make you energetic while working. But what bring this effect to coffee? How does coffee work to our brains?
When we are sober, a sort of hormone called adenosine accumulates in our brains. The more the adenosine accumulates, the more tired you will feel. It is no doubt that the longer you stay sober, the more tired you will feel. On the contrary, while you are sleeping, the amount of adenosine declines and makes you become sober gradually.
According to the experts, the chemical structure of caffeine is smilar to the adenosine's. When caffeine flow to the brains through blood, it starts to take up the receptor against adenosine, and combine with it. But caffeine is not the same as adenosine, it will not make you feel tired or sleepy. Because caffeine occupies the receptor of adenosine that adenosine can't combine with the receptor well, which decreases the effect of adenosine and save you from the feeling of fatigue.
However, if you ingest too much caffeine, your brain creates more receptors of adenosine, and that means you need to drink more coffee if you still want to keep yourself refreshed. At the same time, if you want to get rid of coffee or injest not as much caffeine as you do usually, you may be more tired than the days you don't drink coffee.