Why do I feel uncomfortable if I don’t drink coffee for a day?

Author: Hao Yun

Reviewer: Zhong Kai, Director of the National Food Safety Risk Assessment Center, Kexin Food and Nutrition Information Exchange Center

Coffee is one of the most popular beverages in the world. We all know that drinking coffee can keep people awake. The main ingredient in coffee is caffeine. Some statistics say that more than 100,000 tons of caffeine are consumed worldwide every year, which is equivalent to the total amount of 14 Eiffel Towers. This is very amazing. This shows how much people rely on coffee.

So, why does drinking coffee make people wake up? This has to start with our brain. It turns out that when our body consumes energy, it produces a metabolic waste called adenosine. As more and more energy is consumed every day, more and more adenosine will accumulate.

At this time, our brain will detect these adenosines and react to tell our body that you have consumed enough energy today and it is time to go to sleep. Then, we will start to feel sleepy and want to rest.

Interestingly, from a chemical point of view, the structure of caffeine in coffee is very similar to adenosine. Therefore, when the "detectors" in our brain that are originally used to detect adenosine detect caffeine, all attention will be drawn to it, and the "genuine" adenosine accumulated in the body due to fatigue will be ignored. In other words, caffeine can make these "detectors" "fail", allowing the brain to ignore the fatigue of the body and continue to work. Therefore, drinking coffee can keep many people awake.

However, drinking coffee also requires a good time. Some people don't drink coffee very often, and they have to wait until they are too tired to drink it. At this time, the effect of coffee will be greatly reduced. Why? As we mentioned earlier, there is a "detector" in the brain that detects the metabolic waste adenosine. When you are already very tired, the "detector" in the brain has been busy and has no time to pay attention to caffeine, so the caffeine becomes ineffective. Therefore, it is best to drink coffee before you feel tired.

However, the human brain is still very smart and will not be fooled by caffeine forever. Drinking too much coffee may make people feel awake, but this is just an illusory surface phenomenon. In fact, our body still consumes a lot of energy and produces a lot of adenosine, which still makes our body feel uncomfortable.

So our brain will think, is it that these "detectors" have failed? As a result, more new "detectors" will be generated in the brain to look for adenosine, a waste product produced by metabolism. This means that if you still want to force your brain to stay awake, you need more caffeine. Otherwise, even if you drink coffee, people will still feel sleepy. This is why many people drink more and more coffee. Moreover, when they occasionally can't drink coffee, they will feel particularly uncomfortable. This is actually because there are so many "detectors" in the brain telling the body: You are too tired and should rest early. So when you can't drink coffee, you will have all kinds of headaches and depression.

But don't worry too much. If you don't drink coffee for a long time, in just a few days, the "detector" level in the brain will drop back to normal. From this point of view, the human body's self-regulation ability is still quite strong.

Finally, I would like to remind everyone that although coffee can promote brain alertness, it is not recommended for children under 12 years old. For adolescents aged 12-18, the daily caffeine intake should not exceed 100 mg, which is about the amount of a cup of coffee. If you want to experience the effects of coffee, you should wait until you grow up.