The Chemistry of Caffeine

The chemical works by slowing cell activity, which stimulates the release of adrenaline to increase heart rate, blood flow and muscular activity.

By Diya Chacko
The Dish with Diya

Caffeine is absorbed directly from the stomach into the blood. Graphic: Poulio Mavabmo
Dopamine is a neurotransmitter that produces feelings of reward. Photo: Poulio Mavabmo

Caffeine is absorbed through the stomach into the blood, and takes from 15 to 30 minutes to stimulate the nervous system with the level of caffeine determining the level of stimulation. The normal adult body eliminates the total amount of caffeine in about six to eight hours.

The chemical works by slowing cell activity, which stimulates the release of adrenaline to increase heart rate, blood flow and muscular activity. The levels of dopamine, a neurotransmitter that produces feelings of enjoyment and reward, also increase dramatically.

Negative Effects
The negative effects of caffeine include an increase in anxiety and tension, and a decrease in sleep and reaction time. The effects of caffeine are short-lived in normal doses, and often depend on an individual's metabolism. But a regular intake allows the individual to develop a tolerance for caffeine that might cause headaches when they skip a dose.

Dr. L. Julian Haywood, a professor of cardiovascular medicine at the Keck School of Medicine, said chronic use of coffee might increase the risk of atherosclerosis, or the thickening of arterial walls that reduces blood flow. "The body responds to the stimulant - caffeine - by raising blood pressure," Haywood said. "If you drink too much, the heart may develop an abnormal rhythm, possibly resulting in a heart attack, or worse."

Experts still disagree over whether caffeine can be considered an actual drug. A removal of caffeine from the diet might cause withdrawal symptoms in the form of headaches, an inability to focus and tiredness. These symptoms are relatively mild compared to withdrawal from other drugs such as cocaine, so doctors are unwilling to label caffeine an addictive drug.

Marcello Figueroa, a sophomore majoring in broadcast journalism, said he drinks a lot of soda, but hasn't experienced any withdrawal symptoms.

"I drink about a liter of soda per day," Figueroa said. "I stopped for a while when I felt that I was drinking too much, and started drinking water instead. I didn't get any headaches."