How to identify the good coffee? what's the advantage of drinking a cup of coffee every day?

1. Effect on the central nervous system: caffeine and its structural analogue theophylline are the main active ingredient of coffee.

Coffee tree

Coffee tree

Strong central excitatory effect. But theophylline has a stronger effect and lasts longer than caffeine. People often take caffeine or drink caffeinated drinks.

Now drowsiness is gone, fatigue is reduced, and thinking is quick. With the increase of the dose, the central excitatory effect was more obvious, such as tension, anxiety, restlessness, insomnia, tremor and so on. Higher doses produce local or systemic spasms. The effect of theophylline is stronger than that of caffeine. Methylxanthine compounds such as caffeine and theophylline can increase the sensitivity of respiratory center to CO2. It also has an excitatory effect on the respiratory center, which is more obvious in pathological conditions such as Cheyne-Stoke breathing (Cheyne-Stoke respiration) and apnea in premature infants and in the case of inhibition of respiration with opioids. These compounds can also cause nausea and vomiting, which is partly related to their central role. Taking 85-250mg caffeine can enhance the ability of mental work for long hours and shorten reaction time, but the ability to work involving delicate muscle coordination and accurate timing or arithmetic is reduced. Patients with phobias are particularly sensitive to methylxanthine compounds. In one study, most of these patients showed typical symptoms of anxiety, fear and other phobias when taking caffeine at a plasma concentration of 8 μ g / ml. When the central nervous system is inhibited by drugs, low doses of coffee

Coffee tree

Coffee tree

Methylxanthine compounds such as caffeine can show obvious central excitatory effect. Other data have shown that these compounds can specifically antagonize the effects of opioids including analgesia. Intrathecal injection of caffeine that does not produce hyperalgesia (hyperalgesia) can increase the median effective dose of morphine for pain relief. However, there is no data to show that caffeine can improve brain function during alcoholism. Studies have shown that long-term use of caffeine can lead to tolerance and drug dependence.

two。 Effect on cardiovascular system: methylxanthine compounds such as caffeine and theophylline have obvious effect on circulatory system. But their functions are complex and sometimes contradictory. This largely depends on the state of the body, the dose and whether the drug has been taken before. People who had never used the drug before took caffeine 250-350mg to slightly increase their heart rate, as well as systolic and diastolic blood pressure. However, the above doses often have no effect on people who take caffeine regularly. People who have not taken this kind of compound before take coffee.

Coffee tree

Coffee tree

Whether the increase of heart rate and blood pressure caused by caffeine is related to the increase of catecholamines and plasma renin activity remains to be further studied. It can be considered that for regular users, there is no significant change in the concentration of the above substances in the body. At high doses, both caffeine and theophylline can cause tachycardia. Arrhythmias such as premature contraction may occur in sensitive patients. Excessive consumption of caffeinated drinks can also cause arrhythmias. However, the risk of arrhythmias is small in normal people, and moderate doses of caffeine are usually tolerated in patients with ischemic heart disease or ventricular ectopic (ventricular ectopy). Methylxanthine has a contractile effect on cerebral vessels, resulting in an increase in cerebrovascular resistance, accompanied by a decrease in cerebral blood flow and cerebral oxygen tension.