What are the possible side effects of energy drinks?

Heart palpitations, headaches, respiratory distress, insomnia, tremors/shaking, dizziness, agitation/restlessness, chest pain, gastrointestinal upset, tingling or numbness of the skin. In the case of an overdose, one may experience confusion, breathing trouble, muscle twitches, convulsions, fever, hallucinations, vomiting, increased thirst, irregular or rapid heartbeat, excessive sweating, and an appearance of nervousness.