While the old adage that coffee stunts growth is not true, coffee, or rather the caffeine it contains, does have many effects on the human body's central nervous system, according to TeensHealth. Excessive caffeine consumption from coffee, soda or energy drinks can lead to anxiety, dizziness and an inability to sleep properly.
The amount of caffeine contained in a cup of coffee is highly variable depending on the preparation method and can range from 40 to 120 milligrams, according to Recovery Road Map. In the short term, one or two cups of coffee helps to make a person more alert, less tired and improves thinking and the ability to do physical work. However, drinking too much coffee can increase nervousness, irritability and restlessness. There are no serious long-term effects of drinking one to three cups of coffee per day, but drinking more can lead to insomnia, stomach upset and chronic anxiety.
Coffee has been shown to trigger migraine headaches in some individuals and is not recommended for people with heart problems or those taking certain medications. Coffee is addictive and for regular coffee drinkers, quitting coffee suddenly can lead to a host of unpleasant symptoms, including headaches, fatigue and irritability, according to TeensHealth.