Coffee and tea are the standard life-saving supplies for workers. Why do they sometimes work and sometimes don’t?

As workers who spend more time at work than at home, coffee and tea have become a must-have for maintaining a good working state. Why can these two make us clear-headed? What is the healthy amount of them to drink? Are they suitable for everyone? Let's take a look at the things about coffee and tea.

Image source: soogif

1. Refreshing principle - caffeine

Why can coffee and tea refresh us? This is because their common active ingredient, caffeine, is at work. The reason why caffeine can make people excited is that it can competitively inhibit adenosine receptors. Adenosine is a neuromodulator produced by the body's metabolism. Its main function is to bind to adenosine receptors and convey fatigue signals to the brain. In layman's terms, caffeine can bind to adenosine receptors before adenosine. When a large number of adenosine receptors are occupied, adenosine cannot bind to adenosine receptors. The brain cannot receive fatigue signals, and naturally there is an illusion of "I'm still okay." Therefore, caffeine can suppress fatigue and make people more energetic.

Image source: Yitu.com

Compared with coffee, the caffeine content in tea is relatively low. Tea also contains tea polyphenols, theophylline and other ingredients. Tea polyphenols is a natural antioxidant that can improve brain function and make people feel awake and refreshed by increasing cerebral blood flow, improving oxygen supply and improving cell metabolism. Theophylline is a milder adenosine receptor antagonist than caffeine and can also play the role of caffeine. Therefore, although both coffee and tea contain caffeine, their refreshing principles are similar but not exactly the same.

2. The drinking effect is very different

Although we all drink tea or coffee, why do some people feel full of energy while others are still yawning?

Image source: soogif

Let's first look at coffee. The variety and drinking method of coffee will have a huge impact on the caffeine content. For example, espresso is to extract strong coffee by passing hot water under high pressure through coffee powder. This method usually produces a higher caffeine content. Cold brew coffee is to mix ground coffee powder with cold water and then refrigerate for several hours or overnight. This method produces a lower caffeine content. In a nutshell, the higher the water temperature, the higher the flow rate, the greater the flow rate, and the finer the coffee grind, the higher the caffeine content, and vice versa. In addition, the variety and processing method of coffee beans will also affect the caffeine content. Generally speaking, Robusta coffee: 1.2%-1.5%, Arabica coffee: 0.8%-1.4%, Ripica coffee: 1.4%-2.4%, Indian Mandheling coffee: 1.2%-1.7%. Deep roasted coffee has a lower caffeine content, while lightly roasted coffee has a higher caffeine content.

Image source: Paixin Creative

As for tea, the caffeine content of large-leaf tea is significantly higher than that of small-leaf tea, the caffeine content of buds is higher than that of leaves, and the caffeine content of summer tea is higher than that of spring tea. From the perspective of the environment, the stronger the sunshine, the higher the caffeine content in the tea. In terms of brewing, the caffeine content of hot-brewed tea is higher than that of cold-brewed tea, the caffeine content of broken tea is higher than that of whole tea, and the caffeine content of long-brewed tea is higher than that of quick-brewed tea.

Image source: Yitu.com

After excluding these external factors, if a person drinks coffee or tea regularly, he may have developed tolerance to these drinks, and even if he drinks coffee or tea, he will not feel a significant refreshing effect. For some people, if the amount of consumption is insufficient, it is difficult to feel the refreshing effect of coffee or tea. Because the ingredients such as caffeine contained in coffee and tea require a certain amount to produce an effect, if the amount consumed is too small, it is not enough to cause a significant effect. In addition, some people are born with a weak ability to metabolize caffeine, or have poor liver function and cannot metabolize caffeine quickly, resulting in a lack of obvious refreshing effect of coffee or tea. A person's mental state may also affect the refreshing effect of coffee or tea. If a person is physically and mentally exhausted, stressed or depressed, it is difficult to feel a significant refreshing effect even if he drinks coffee or tea.

Image source: Paixin Creative

3. Drinking time is important

Drinking coffee or tea before feeling sleepy can prevent fatigue and sleepiness in advance when you are in a good mental state. In this case, the ingredients in coffee or tea can stimulate the central nervous system, increase the excitability of the cerebral cortex, and keep people awake and alert. If you drink coffee or tea after feeling sleepy, since your body is already very tired, a higher dose of caffeine is needed to produce an effective refreshing effect, but this may cause some side effects, such as increased heart rate, anxiety, insomnia, etc. Therefore, the refreshing effect of drinking coffee or tea when you are already tired may not be as obvious as drinking it before fatigue.

Image source: Paixin Creative

In addition, the effect of drinking coffee or tea before feeling sleepy is also related to the amount consumed and personal physique. If the amount consumed is too large, it may cause discomfort symptoms such as excessive excitement and palpitations, and for some people, the ingredients in coffee or tea may cause allergic reactions or adverse reactions. Therefore, the refreshing effects of drinking coffee or tea before feeling sleepy and drinking it after feeling sleepy may be different. The choice and amount of consumption should be controlled according to personal physique and situation. As for before going to bed, you should avoid drinking such stimulating drinks.

4. Healthy drinking varies from person to person

Although coffee and tea are delicious and refreshing, excessive consumption can still have negative effects on health. It is recommended that people consume no more than 400 mg of caffeine per day, which is roughly equivalent to 2-4 cups of regular coffee or 5-6 cups of tea (of course, the specific amount of consumption varies from person to person). Exceeding this amount may cause symptoms such as headaches, palpitations, insomnia, anxiety, diarrhea, etc.

Image source: Paixin Creative

In addition, caffeine can increase urine output and may lead to dehydration, so remember to replenish water after drinking a lot of coffee or tea. For people with cardiovascular disease or high blood pressure, caffeine in coffee or tea may cause symptoms such as palpitations and increased blood pressure; pregnant or breastfeeding women should limit their coffee or tea intake because caffeine can pass through the placenta or breast milk into the fetus or baby; patients with anemia and hemochromatosis should avoid drinking tea because the tannic acid in tea may affect the body's absorption of iron, aggravating or causing anemia; some drugs interact with coffee or tea, resulting in reduced efficacy or increased side effects, so people who are taking medication should consult a doctor before drinking coffee or tea.

The author of this article: Tan Hao, doctor and acne-squeezing master.

Audit expert: Huang He

Source: Chongqing Science and Technology Museum

Statement: Except for original content and special notes, some pictures are from the Internet. They are not for commercial purposes and are only used as popular science materials. The copyright belongs to the original authors. If there is any infringement, please contact us to delete them.