What is caffeine? What are the effects of caffeine on the human body? Recommended daily coffee intake

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In the fast-paced modern society, a cup of coffee in the morning has become an indispensable part of most people's lives. In addition to those who like coffee, I believe that more people drink coffee in order to refresh their minds. Even if you like coffee, Qianjie also advises you not to drink too much coffee, because coffee contains caffeine. In fact, you need to pay attention to drinking coffee.

What is caffeine?

Caffeine, a sobering substance in coffee, has been found to relieve fatigue and refresh people by chewing on specific parts of certain plants as early as ancient times. it was not until modern times that we separated caffeine from plants alone. and widely used in various diets in modern society. Tea, chocolate and carbonated drinks also contain caffeine, so it is difficult to avoid caffeine in daily life.

Why is caffeine refreshing?

The main reason for the refreshing effect of caffeine is that its molecular structure is very close to that of a substance in our body called adenosine, an endogenous nucleoside found in human cells. when it binds to adenosine receptors on our neurons, it slows down the activity of the central nervous system, and the longer people stay awake, the more they accumulate in the body.

Mccully of Harvard Medical School in the United States believes that the accumulation of adenosine in the brain is related to the period of sleep. When adenosine increases to a certain extent and binds to receptors on neurons, it slows down the activity of neurons and makes the brain go to sleep, when metabolism slows down and adenosine decreases gradually. It is only when the neurons slowly become active that people wake up. However, in this process, the amount of adenosine in the human body has not actually decreased, so even if caffeine is used to keep the brain awake for a while, after caffeine is metabolized by the body for a period of time, the sudden drowsiness will be more violent than usual. If you use caffeine to stay awake longer, the body may need longer sleep to get rid of the accumulated adenosine.

The good or bad effects of long-term caffeine intake on the human body?

The benefit of caffeine is that it can keep people awake, increase alertness, and promote muscle activity in a short period of time. There have been many sports-related research papers in China on how to use caffeine to enhance the physical ability of athletes. In addition, caffeine can also enhance blood circulation, long-term intake can reduce the risk of high blood pressure and prevent heart disease.

However, if a person consumes more caffeine than the recommended amount for a long time, the number of adenosine receptors in the brain will gradually increase, and they will be more sensitive to the changes in adenosine or caffeine in the body. If caffeine intake is suddenly interrupted, the extra receptors will bind to adenosine in the body in a shorter time than usual. Adenosine binds to receptors more than is needed to make people feel sleepy, so we look for more caffeine to keep the brain awake. This is synonymous with what is commonly known as (coffee addiction).

But a strictly defined addiction is that as the use of drugs increases, the body becomes more resistant to the drugs, resulting in a weakening of the drug's effect, which means that more drugs are needed to get the same stimulation as in the past. However, this is not very consistent with caffeine. At a safe dose, the average person will not drink more and more coffee at a fixed cup of coffee a day. Even if you break the habit because of something, you will only feel a little uncomfortable and will not have the same serious withdrawal symptoms as drug addiction. it just means that the person is dependent on caffeine.

How long does it take to drink coffee before going to bed so that it won't affect your sleep?

According to Drake C, Roehrs T, Shambroom J and Roth T. The study in < Caffeine effects on sleep taken0, 3, or 6 hours before going to bed. > (Note 2) shows that consuming 400mg of caffeine before bed, three hours or six hours before bed reduces total sleep time by nearly an hour. It can be seen that drinking coffee even six hours before going to bed can affect sleep. In addition, according to Landolt HP, Werth E, Borbely AA and Dijk DJ. According to the Caffeine intake (200 mg) in the morning affects human sleep and EEG power spectra at night.Brain Res. Study, starting at 7 a.m. and reducing caffeine by 200mg, looking at the effect of caffeine on the body from another perspective, it was found that caffeine intake 16 hours ago had little effect on the body. Overall, the amount of coffee consumed and the age, liver function, smoking, infrequent consumption of coffee and pregnancy can also affect the body's metabolism of caffeine.

Can adults, children and pregnant women drink coffee? Recommended daily caffeine intake

According to the most widely cited caffeine study written by Nawrot in 2003, a healthy adult with a weight of 65 kg has a maximum recommended daily intake of 400mg (equivalent to four cups of black coffee), which is not harmful to the human body, and this number will increase or decrease as a result of body weight. The maximum recommended intake per person per day is 300 milligrams (equivalent to a large cup of 7-11 iced American coffee). If you can intelligently control your caffeine intake according to your condition, you can quickly boost your spirits to face the challenges of life at the beginning of the day.

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