Coffee contains caffeine, which helps to improve alertness, sensitivity, memory and attention.

There is a conductive substance called adenosine in the human body, which can control nerve activity, leading to slow breathing, weakened mood, reduced gastric acid secretion and diuresis. Caffeine will fake adenosine, which will make the body think that adenosine is acting, make you feel energetic, increase your stomach acid, urinate more frequently, and naturally you can't sleep.

It is worth noting that the short-term wakefulness caused by caffeine does not mean that physical strength has really recovered. In addition, everyone has different metabolic rate and sensitivity to caffeine, so some people don't feel that their sleep is affected after drinking coffee. Therefore, having a cup of hot coffee after getting up in the morning can refresh your mind and make you feel more comfortable, but you may lose sleep at night.

Extended data:

The benefits of coffee:

1. Drinking coffee often can prevent radiation injury. Radiation hazards, especially electrical radiation, have become the prominent pollution at present. The Indian atomic researchers in Baba came to this conclusion in mouse experiments and said it can be applied to people.

2. Coffee is good for the skin. Coffee can promote metabolic function, activate digestive organs and play a great role in constipation. Bathing with coffee powder is a kind of hyperthermia, which has the function of losing weight.

3, coffee has the effect of hangover. Drinking coffee after drinking will quickly oxidize acetaldehyde converted by alcohol, decompose it into water and carbon dioxide and excrete it.

4, coffee can eliminate fatigue. To eliminate fatigue, we must supplement nutrition, rest and sleep, and promote metabolic functions, and coffee has these functions.

5. Three cups of coffee a day can prevent gallstones. For caffeinated coffee, it can stimulate gallbladder contraction and reduce cholesterol which is easy to form gallstones in bile. Recently, researchers at Harvard University found that men who drink two or three cups of coffee a day have a lower risk of gallstones than 40%.

6. The health function of coffee. Coffee has the functions of resisting oxidation, protecting the heart, strengthening bones and muscles, benefiting the waist and knees, stimulating appetite, promoting eating, reducing fat and digestion, inducing resuscitation and removing dampness, promoting blood circulation and removing blood stasis, calming wind and relieving spasm.

Reference: Baidu Encyclopedia-Coffee