Caffeine is a chemical compound found naturally in tea, coffee, cacao, yerba mate, and guarana seeds. This extremely bitter substance acts as a central nervous stimulant. Increased respiration, heart rate, and blood pressure are common side affects when large quantities are consumed. Caffeine acts on the central nervous system by blocking neural receptors causing a release of epinephrine, and dopamine. The resulting action is similar to amphetamines. Prolonged caffeine use can lead to insomnia, head aches an high blood pressure. When
consumed in small quantities as with green tea, caffeine can improve alertness and concentration. Unlike many other stimulants, caffeine is quickly and completely removed from the brain. Caffeine is also a natural diuretic, removing excess water from the body. Used in moderation, caffeine aids weight loss by burning additional calories through a process known as thermogenesis.
Research is now being done on its effect on preventing Parkinson's disease. Green tea contains considerably less caffeine than coffee, making it a safe and healthy beverage. The stimulating boost of energy from caffeine has led to its abuse in highly caffeinated soft drinks, energy drinks and sports beverages. Drink green tea for the health benefits and enjoy a modest uplift during the day.