Why can tea refresh you?

Nowadays, people are under great pressure in life. In order to adapt to the development of society in time, some people will study by working overtime and staying up late. At night, people's spirits are very poor and they can't concentrate. There are many drinks that can refresh people, such as coffee and tea. However, coffee tastes very bitter and is not easily accepted by everyone. So why can tea refresh people?

First, why can tea refresh you? Tea can refresh you because it contains a substance called caffeine. Caffeine is a central nervous system stimulant and therefore has a refreshing effect. When the tea leaves have been brewed for about 3 minutes, most of the caffeine in the tea leaves has dissolved into the tea. At this time, the tea has obvious refreshing effect and makes people excited.

Second, caffeine is a bioalkaloid found in tea at a very high content, generally at 2-5%. Each 150 ml cup of tea contains about 40 mg of caffeine. Caffeine has many pharmacological effects on the human body, such as refreshing, diuretic, promoting blood circulation, and aiding digestion. Tea can refresh you because of the caffeine in it. Caffeine has a bitter taste. The caffeine content varies greatly in different parts of the tea tree, with the highest content in the leaves and less in the stems. It decreases in the new shoots as the leaves age and changes significantly with the seasons. Generally, the content of caffeine is higher in summer tea than in spring tea.

Although tea is a healthy drink, drinking too much is not good. The caffeine in tea takes three or four hours to be fully absorbed by the human body, so it is best not to drink too much tea before going to bed. In addition, pregnant women and people with cold body should not drink too much. Drinking tea can maintain physical strength for two reasons: on the one hand, the caffeine in tea can stimulate muscles and stimulate their functions, thereby increasing the efficiency of exercise and physical labor. Tea is rich in vitamin C, which can give the body stamina, endurance and energy. On the other hand, after intense exercise, you will inevitably sweat. Sweating has no effect on your health, but at the same time, the water-soluble vitamin C in the sweat will also be lost. At this time, simply drinking water is not appropriate, because drinking too much water will dilute the gastric juice, hinder stomach function, and lead to increased fatigue.