Caffeine.... Harmful? Hyper? Anything...?

Site #1: http://www.nlm.nih.gov/medlineplus/caffeine.html
There are many sources where we can find caffeine. Some sources are very common useage of caffeine in our daily life, such as coffee, tea, and soft drinks. Caffeine can affect our body in many different ways, such as our body's metabolism and our nervous system. Two to four cups of caffeine usage per day will not be too harmful, however, overuse of caffeine could cause serious problems in very day life. It will be harder for us to fall asleep, easily to get angry, and easily to get angry.It might also give you headaches, and sometimes it might also get your heart into trouble. Everyone has different limit in the usage of caffeine, however, we know that a pregnant woman, because it is not good for the baby.

Site #2: http://www.mayoclinic.com/health/caffeine/AN01211
According to this website, I now know the exact amount of the range of caffeine we can use per day, which the highest is 500-600 mg. It seems like a very big range, however, there are so many sources that we eat that contains a lot of caffeine, such as diet coke, Starbucks, Mountain Dew, Hersey's chocolate, and so many more. Let's say you drink 3 cups of 16 oz Starbucks vanilla latte a day, you are already in a very dangerous range of over using caffeine, which is very bad for your health. We must then know about some statistic of caffeine that are very common in our daily life, and plan how to use caffeine safe with these numbers of caffeine contains.

Site #3: http://kidshealth.org/teen/food_fitness/nutrition/caffeine.html
Caffeine are mostly consumed in soft drinks along with sugar for most teens. It will not be store as nutrient in our body but it will have direct effects on our bodies. Shorter people are should drink caffeine less than other. Also, if the more a person consume caffeine, the less reactive will the caffeine be to the person. It is unlike wine, you could actually make your limit of caffeine larger than before, however, it is not healthy to do that. Caffeine causes people to want to go to bathroom more, because of this, it is better to avoid to use caffeine on hot weather, so that you will not use all of your water in your body when you are sweating at the same time. Caffeine could also causes your bones to lose its tightness, which could cause serious bone disease. Caffeine can sometimes be use for medicine, however, bad usage of caffeine could also make a sickness even worse. For teens, we should not use caffeine more than 100 mg per day, not only it affects our health, but also it affects our growing speed. Too much caffeine is not good for us, however, it is not a good idea to cut it down too fast, because it could also get you sick.Try to substitute your caffeine source with other source that contains less or none caffeine until you reach 100 mg per day, then you are successful in your cut down caffeine process.
Site #4: http://www.nlm.nih.gov/medlineplus/ency/article/002579.htm
Site #5: http://science.howstuffworks.com/caffeine.htm
Site #6: http://www.energyfiend.com/the-caffeine-database