The main effectors contained in coffee is caffeine. Caffeine effects on adenosine receptor antagonist, increases blood pressure and homocysteine??, stimulate fat oxidation and the release of free fatty acids, and decreased insulin sensitivity.
On the other hand, in addition to caffeine, coffee also contains various other components, such as antioxidants, potassium, niacin, magnesium and other fitokemikal opposite, protective effect on the cardiovascular system.
Various studies show caffeine content of 200 mg (280 grams or 10 ounces of coffee) can significantly improve the ability to concentrate, especially when he is sleepy, but excessive caffeine content does not give better results. A single dose of 500 mg of caffeine showed worsening of the ability to think most individuals. Caffeine is generally relatively harmless if used moderately (2 cups a day), but with higher doses, caffeine can cause anxiety symptoms (anxiety), such as sweating, tense and unable to concentrate. High doses of caffeine can also lead to loss of bone density in middle-aged women and lead to pain in middle-aged women with benign fibrocystic breast abnormalities.
Individual reactions to caffeine varies daily habits in consuming coffee. On a regular coffee drinker, not a coffee can cause headaches, fatigue, deterioration of mental ability and mood. If coffee is consumed again, then these symptoms will disappear.
Caffeine is a stimulant that affects increased respiratory rate, heart rate, blood pressure and the secretion of stress hormones and other hormones. Moderate doses of caffeine can increase the metabolic energy expenditure (metabolic rate the body) within a few hours, stimulates the digestive tract and diuretic effects (lots of pee).