You are drinking lots of cola at a party, when it suddenly hits. You are full of energy, you jump around, and you talk too fast. Later you can't fall asleep and the next day you're tired and feel awful. Does that sound familiar? Most children already have a lot of energy, but kids who drink a lot of cola often end up even more wired than usual. The drink includes a lot of sugar but also a chemical that produces a lot of energy - caffeine. Like cola, coffee is full of caffeine. That's why many adults drink it the first thing in the morning to help them wake up. The chemical is naturally found in tea, chocolate and hot cocoa. Because many people need this kick, food producers often add it to many other beverages, energy drinks and snacks. But is caffeine good or bad for us? Some studies have shown that caffeine might help people respond to things more quickly. Scientists have found out that caffeinated coffee and tea can help protect your heart, brain and other organs from disease. On the other hand too much caffeine can make people anxious and unable to sleep. This is worrisome because we need sleep to stay healthy. Caffeine may also raise your blood pressure, increase your heart rate and make you feel more stressed. Love it or hate it, caffeine is hard to avoid. Coffee shops are all over the place, in city streets and malls. Machines offer coffee and cola at schools. Even though you can get caffeine-free coffee, tea and cola almost everywhere more than 80% of adults in America consume caffeine regularly. Caffeine raises the amount of sugar in your bloodstream, even if there is no sugar in your caffeinated drink. That's what gives you extra energy. Taking caffeine away from regular users causes withdrawal symptoms, like headaches and sleepiness. It also makes them react more slowly. So when you give these people the caffeine that they need they do better and react more quickly. Many athletes take caffeine to boost their energy. Studies show however that caffeine only helps those athletes who are in good condition already. In an experiment runners had to run at a very fast pace. On average they were able to run for about 32 minutes. After taking caffeine they ran 7 to 10 minutes longer. Although caffeine may be good for world class athletes, it may harm the health of people who are overweight. In some people it may even lead to diabetes. In the end a cup of coffee or a can of cola once in a while is okay, but don't overdo it!