What does caffeine do to your body?

Caffeine is well absorbed by the body, and the short-term effects are usually experienced between 5 and 30 minutes after having it. These effects can include increased breathing and heart rate, and increased mental alertness and physical energy. Depending on the individual, these effects can last up to 12 hours.
Some of the signs and symptoms of having too much caffeine include: a rise in body temperature,frequent urination,dehydration,dizziness and headaches,rapid heartbeat (palpitations),restlessness and excitability,anxiety and irritability,trembling hands,sleeplessness,first feeling energetic but then having an even greater feeling of tiredness.