This is default featured slide 1 title
This is default featured slide 2 title
 

caffein benefit

Caffeine is the most commonly consumed psychoactive drug in the world, and some of its behavioral effects (such as arousal) may resemble those produced by cocaine, amphetamines, and other stimulants. Coffee consumption accounts for about 75% of the adult intake of caffeine in the United States, although that might be changing among younger adults with the growing popularity of energy drinks.

The caffeine content of coffee varies greatly, depending on the beans, how they’re roasted, and other factors, but the average for an 8-ounce cup is about 100 milligrams (mg). Tea has about half as much caffeine as coffee. Decaffeinated coffee has some caffeine, but the 2 to 4 mg in an 8-ounce cup is a smidgen compared with the caffeinated version. The lethal dose of caffeine is about 10 grams, which is equivalent to the amount of caffeine in 100 cups of coffee.

Caffeine gets absorbed in the stomach and small intestine and then distributed throughout the body, including the brain. The amount circulating in the blood peaks 30 to 45 minutes after it’s ingested and only small amounts are around eight to 10 hours later. In between, the amount circulating declines as caffeine gets metabolized in the liver.

Tobacco and marijuana accelerate caffeine metabolism, which reduces the time caffeine circulates in the body. Oral contraceptives slow it down, so they have the opposite effect. Researchers have identified genes that influence a person’s natural risk of caffeine metabolism, which might explain why some people are exquisitely sensitive to caffeine while others are not.

Caffeine probably has multiple targets in the brain, but the main one seems to be adenosine receptors. Adenosine is a brain chemical that dampens brain activity. By hogging adenosine’s receptors, caffeine sets off a chain of events that affects the activity of dopamine, another important brain chemical, and the areas of the brain involved in arousal, pleasure, and thinking. A part of the brain affected by Parkinson’s disease, called the striatum, has many adenosine receptors; by docking on them, caffeine seems to have some protective effects.

Outside the brain, caffeine can be a performance enhancer, boosting the strength of muscle contraction and offsetting some of the physiological and psychological effects of physical exertion. But, especially in the short term, it also has negative effects, which include raising blood pressure, making arteries stiffer, and increasing levels of homocysteine, insulin, and possibly cholesterol. Habitual use may cause some of these effects to wear off. For some conditions, though, coffee may have some benefit despite, rather than because of, caffeine.