Drinks such as coffee, tea, and many soft drinks contain caffeine. It is also found in medications for staying awake, dieting, treating colds, allergies, migraines and muscle tension. Americans consume an average of 200 milligrams of caffeine a day. This Is equivalent to 2 cups of coffee, 3-4 cans of soda, or 4 cups of tea. Many students rely on it to wake up, stay alert during class, and keep them awake for late night studying.
Caffeine stimulates the central nervous system.
Its effects range from mild alertness to heightened anxiety and body tension. It shortens reaction time among some users. Caffeine can be habit-forming. Some regular users who give it up may experience withdrawal symptoms 12-16 hours after the last dose. In addition, coffee nerves can cause behaviors that may add tension to interpersonal interactions.